diff --git a/CMakeLists.txt b/CMakeLists.txt
index 6ab79d69..eb6150f8 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -10,7 +10,7 @@ else()
     add_compile_options(-Wall -Wextra -Werror)
 endif()
 
-find_package(Python COMPONENTS Interpreter Development.Module NumPy REQUIRED)
+find_package(Python COMPONENTS Interpreter Development.Module REQUIRED)
 
 # Detect the installed nanobind package and import it into CMake
 execute_process(
diff --git a/NUMPY_LICENSE.txt b/NUMPY_LICENSE.txt
deleted file mode 100644
index 4723d4ea..00000000
--- a/NUMPY_LICENSE.txt
+++ /dev/null
@@ -1,30 +0,0 @@
-Copyright (c) 2005-2021, NumPy Developers.
-All rights reserved.
-
-Redistribution and use in source and binary forms, with or without
-modification, are permitted provided that the following conditions are
-met:
-
-    * Redistributions of source code must retain the above copyright
-       notice, this list of conditions and the following disclaimer.
-
-    * Redistributions in binary form must reproduce the above
-       copyright notice, this list of conditions and the following
-       disclaimer in the documentation and/or other materials provided
-       with the distribution.
-
-    * Neither the name of the NumPy Developers nor the names of any
-       contributors may be used to endorse or promote products derived
-       from this software without specific prior written permission.
-
-THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/pyproject.toml b/pyproject.toml
index 05037d6b..73a3ca67 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -2,7 +2,6 @@
 requires = [
   "scikit-build-core",
   "nanobind",
-  "oldest-supported-numpy",  # only needed for datetime
 ]
 build-backend = "scikit_build_core.build"
 
@@ -69,7 +68,7 @@ build = "cp39-*64 cp310-*64 cp311-*64 cp312-*64"
 skip = "*musllinux*"
 
 test-command = "pytest {project}/tests"
-test-requires = ["pytest", "pandas>=2.0.0", "polars<1.3.0", "narwhals", "numpy"]
+test-requires = ["pytest", "pandas>=2.0.0", "polars<1.3.0", "narwhals"]
 
 [tool.ruff]
 line-length = 88
diff --git a/src/pantab/CMakeLists.txt b/src/pantab/CMakeLists.txt
index db79484d..6a3d2674 100644
--- a/src/pantab/CMakeLists.txt
+++ b/src/pantab/CMakeLists.txt
@@ -2,7 +2,6 @@ set(PANTAB_SOURCES
   libpantab.cpp
   reader.cpp
   writer.cpp
-  numpy_datetime.cpp
 )
 if(WIN32)
   # Required so local installation of pantab can resolve to bundled
@@ -17,7 +16,6 @@ nanobind_add_module(
   NOMINSIZE
   ${PANTAB_SOURCES}
 )
-target_include_directories(libpantab PUBLIC ${Python_NumPy_INCLUDE_DIRS})
 target_link_libraries(libpantab
   PRIVATE Tableau::tableauhyperapi-cxx
   PRIVATE nanoarrow
diff --git a/src/pantab/numpy_datetime.cpp b/src/pantab/numpy_datetime.cpp
deleted file mode 100644
index 46fe7c38..00000000
--- a/src/pantab/numpy_datetime.cpp
+++ /dev/null
@@ -1,447 +0,0 @@
-/*
- * This file implements core functionality for NumPy datetime.
- *
- * Written by Mark Wiebe (mwwiebe@gmail.com)
- * Copyright (c) 2011 by Enthought, Inc.
- *
- * This file is derived from NumPy 1.20. See NUMPY_LICENSE.txt
- */
-
-#include "numpy_datetime.h"
-
-#define PY_SSIZE_T_CLEAN
-#include <Python.h>
-
-#include <time.h>
-
-#define NO_IMPORT_ARRAY
-#define PY_ARRAY_UNIQUE_SYMBOL PANTAB_ARRAY_API
-#include <numpy/arrayobject.h>
-
-/*
- * Computes the python `ret, d = divmod(d, unit)`.
- *
- * Note that GCC is smart enough at -O2 to eliminate the `if(*d < 0)` branch
- * for subsequent calls to this command - it is able to deduce that `*d >= 0`.
- */
-static inline npy_int64 extract_unit_64(npy_int64 *d, npy_int64 unit) {
-  assert(unit > 0);
-  npy_int64 div = *d / unit;
-  npy_int64 mod = *d % unit;
-  if (mod < 0) {
-    mod += unit;
-    div -= 1;
-  }
-  assert(mod >= 0);
-  *d = mod;
-  return div;
-}
-
-/* Days per month, regular year and leap year */
-int _days_per_month_table[2][12] = {
-    {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
-    {31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}};
-
-/*
- * Returns 1 if the given year is a leap year, 0 otherwise.
- */
-int is_leapyear(npy_int64 year) {
-  return (year & 0x3) == 0 && /* year % 4 == 0 */
-         ((year % 100) != 0 || (year % 400) == 0);
-}
-
-/*
- * Calculates the days offset from the 1970 epoch.
- */
-npy_int64 get_datetimestruct_days(const npy_datetimestruct *dts) {
-  int i, month;
-  npy_int64 year, days = 0;
-  int *month_lengths;
-
-  year = dts->year - 1970;
-  days = year * 365;
-
-  /* Adjust for leap years */
-  if (days >= 0) {
-    /*
-     * 1968 is the closest leap year before 1970.
-     * Exclude the current year, so add 1.
-     */
-    year += 1;
-    /* Add one day for each 4 years */
-    days += year / 4;
-    /* 1900 is the closest previous year divisible by 100 */
-    year += 68;
-    /* Subtract one day for each 100 years */
-    days -= year / 100;
-    /* 1600 is the closest previous year divisible by 400 */
-    year += 300;
-    /* Add one day for each 400 years */
-    days += year / 400;
-  } else {
-    /*
-     * 1972 is the closest later year after 1970.
-     * Include the current year, so subtract 2.
-     */
-    year -= 2;
-    /* Subtract one day for each 4 years */
-    days += year / 4;
-    /* 2000 is the closest later year divisible by 100 */
-    year -= 28;
-    /* Add one day for each 100 years */
-    days -= year / 100;
-    /* 2000 is also the closest later year divisible by 400 */
-    /* Subtract one day for each 400 years */
-    days += year / 400;
-  }
-
-  month_lengths = _days_per_month_table[is_leapyear(dts->year)];
-  month = dts->month - 1;
-
-  /* Add the months */
-  for (i = 0; i < month; ++i) {
-    days += month_lengths[i];
-  }
-
-  /* Add the days */
-  days += dts->day - 1;
-
-  return days;
-}
-
-/*
- * Modifies '*days_' to be the day offset within the year,
- * and returns the year.
- */
-static npy_int64 days_to_yearsdays(npy_int64 *days_) {
-  const npy_int64 days_per_400years = (400 * 365 + 100 - 4 + 1);
-  /* Adjust so it's relative to the year 2000 (divisible by 400) */
-  npy_int64 days = (*days_) - (365 * 30 + 7);
-  npy_int64 year;
-
-  /* Break down the 400 year cycle to get the year and day within the year */
-  year = 400 * extract_unit_64(&days, days_per_400years);
-
-  /* Work out the year/day within the 400 year cycle */
-  if (days >= 366) {
-    year += 100 * ((days - 1) / (100 * 365 + 25 - 1));
-    days = (days - 1) % (100 * 365 + 25 - 1);
-    if (days >= 365) {
-      year += 4 * ((days + 1) / (4 * 365 + 1));
-      days = (days + 1) % (4 * 365 + 1);
-      if (days >= 366) {
-        year += (days - 1) / 365;
-        days = (days - 1) % 365;
-      }
-    }
-  }
-
-  *days_ = days;
-  return year + 2000;
-}
-
-/*
- * Fills in the year, month, day in 'dts' based on the days
- * offset from 1970.
- */
-static void set_datetimestruct_days(npy_int64 days, npy_datetimestruct *dts) {
-  int *month_lengths, i;
-
-  dts->year = days_to_yearsdays(&days);
-  month_lengths = _days_per_month_table[is_leapyear(dts->year)];
-
-  for (i = 0; i < 12; ++i) {
-    if (days < month_lengths[i]) {
-      dts->month = i + 1;
-      dts->day = (int)days + 1;
-      return;
-    } else {
-      days -= month_lengths[i];
-    }
-  }
-}
-
-/*
- * Converts a datetime from a datetimestruct to a datetime based
- * on some metadata. The date is assumed to be valid.
- *
- * TODO: If meta->num is really big, there could be overflow
- *
- * Returns 0 on success, -1 on failure.
- */
-int convert_datetimestruct_to_datetime(PyArray_DatetimeMetaData *meta,
-                                       const npy_datetimestruct *dts,
-                                       npy_datetime *out) {
-  npy_datetime ret;
-  NPY_DATETIMEUNIT base = meta->base;
-
-  /* If the datetimestruct is NaT, return NaT */
-  if (dts->year == NPY_DATETIME_NAT) {
-    *out = NPY_DATETIME_NAT;
-    return 0;
-  }
-
-  /* Cannot instantiate a datetime with generic units */
-  if (meta->base == NPY_FR_GENERIC) {
-    PyErr_SetString(PyExc_ValueError,
-                    "Cannot create a NumPy datetime other than NaT "
-                    "with generic units");
-    return -1;
-  }
-
-  if (base == NPY_FR_Y) {
-    /* Truncate to the year */
-    ret = dts->year - 1970;
-  } else if (base == NPY_FR_M) {
-    /* Truncate to the month */
-    ret = 12 * (dts->year - 1970) + (dts->month - 1);
-  } else {
-    /* Otherwise calculate the number of days to start */
-    npy_int64 days = get_datetimestruct_days(dts);
-
-    switch (base) {
-    case NPY_FR_W:
-      /* Truncate to weeks */
-      if (days >= 0) {
-        ret = days / 7;
-      } else {
-        ret = (days - 6) / 7;
-      }
-      break;
-    case NPY_FR_D:
-      ret = days;
-      break;
-    case NPY_FR_h:
-      ret = days * 24 + dts->hour;
-      break;
-    case NPY_FR_m:
-      ret = (days * 24 + dts->hour) * 60 + dts->min;
-      break;
-    case NPY_FR_s:
-      ret = ((days * 24 + dts->hour) * 60 + dts->min) * 60 + dts->sec;
-      break;
-    case NPY_FR_ms:
-      ret = (((days * 24 + dts->hour) * 60 + dts->min) * 60 + dts->sec) * 1000 +
-            dts->us / 1000;
-      break;
-    case NPY_FR_us:
-      ret = (((days * 24 + dts->hour) * 60 + dts->min) * 60 + dts->sec) *
-                1000000 +
-            dts->us;
-      break;
-    case NPY_FR_ns:
-      ret = ((((days * 24 + dts->hour) * 60 + dts->min) * 60 + dts->sec) *
-                 1000000 +
-             dts->us) *
-                1000 +
-            dts->ps / 1000;
-      break;
-    case NPY_FR_ps:
-      ret = ((((days * 24 + dts->hour) * 60 + dts->min) * 60 + dts->sec) *
-                 1000000 +
-             dts->us) *
-                1000000 +
-            dts->ps;
-      break;
-    case NPY_FR_fs:
-      /* only 2.6 hours */
-      ret = (((((days * 24 + dts->hour) * 60 + dts->min) * 60 + dts->sec) *
-                  1000000 +
-              dts->us) *
-                 1000000 +
-             dts->ps) *
-                1000 +
-            dts->as / 1000;
-      break;
-    case NPY_FR_as:
-      /* only 9.2 secs */
-      ret = (((((days * 24 + dts->hour) * 60 + dts->min) * 60 + dts->sec) *
-                  1000000 +
-              dts->us) *
-                 1000000 +
-             dts->ps) *
-                1000000 +
-            dts->as;
-      break;
-    default:
-      /* Something got corrupted */
-      PyErr_SetString(PyExc_ValueError,
-                      "NumPy datetime metadata with corrupt unit value");
-      return -1;
-    }
-  }
-
-  /* Divide by the multiplier */
-  if (meta->num > 1) {
-    if (ret >= 0) {
-      ret /= meta->num;
-    } else {
-      ret = (ret - meta->num + 1) / meta->num;
-    }
-  }
-
-  *out = ret;
-
-  return 0;
-}
-
-/*
- * Converts a datetime based on the given metadata into a datetimestruct
- */
-int convert_datetime_to_datetimestruct(PyArray_DatetimeMetaData *meta,
-                                       npy_datetime dt,
-                                       npy_datetimestruct *out) {
-  npy_int64 days;
-
-  /* Initialize the output to all zeros */
-  memset(out, 0, sizeof(npy_datetimestruct));
-  out->year = 1970;
-  out->month = 1;
-  out->day = 1;
-
-  /* NaT is signaled in the year */
-  if (dt == NPY_DATETIME_NAT) {
-    out->year = NPY_DATETIME_NAT;
-    return 0;
-  }
-
-  /* Datetimes can't be in generic units */
-  if (meta->base == NPY_FR_GENERIC) {
-    PyErr_SetString(PyExc_ValueError,
-                    "Cannot convert a NumPy datetime value other than NaT "
-                    "with generic units");
-    return -1;
-  }
-
-  /* TODO: Change to a mechanism that avoids the potential overflow */
-  dt *= meta->num;
-
-  /*
-   * Note that care must be taken with the / and % operators
-   * for negative values.
-   */
-  switch (meta->base) {
-  case NPY_FR_Y:
-    out->year = 1970 + dt;
-    break;
-
-  case NPY_FR_M:
-    out->year = 1970 + extract_unit_64(&dt, 12);
-    out->month = dt + 1;
-    break;
-
-  case NPY_FR_W:
-    /* A week is 7 days */
-    set_datetimestruct_days(dt * 7, out);
-    break;
-
-  case NPY_FR_D:
-    set_datetimestruct_days(dt, out);
-    break;
-
-  case NPY_FR_h:
-    days = extract_unit_64(&dt, 24LL);
-    set_datetimestruct_days(days, out);
-    out->hour = (int)dt;
-    break;
-
-  case NPY_FR_m:
-    days = extract_unit_64(&dt, 60LL * 24);
-    set_datetimestruct_days(days, out);
-    out->hour = (int)extract_unit_64(&dt, 60LL);
-    out->min = (int)dt;
-    break;
-
-  case NPY_FR_s:
-    days = extract_unit_64(&dt, 60LL * 60 * 24);
-    set_datetimestruct_days(days, out);
-    out->hour = (int)extract_unit_64(&dt, 60LL * 60);
-    out->min = (int)extract_unit_64(&dt, 60LL);
-    out->sec = (int)dt;
-    break;
-
-  case NPY_FR_ms:
-    days = extract_unit_64(&dt, 1000LL * 60 * 60 * 24);
-    set_datetimestruct_days(days, out);
-    out->hour = (int)extract_unit_64(&dt, 1000LL * 60 * 60);
-    out->min = (int)extract_unit_64(&dt, 1000LL * 60);
-    out->sec = (int)extract_unit_64(&dt, 1000LL);
-    out->us = (int)(dt * 1000);
-    break;
-
-  case NPY_FR_us:
-    days = extract_unit_64(&dt, 1000LL * 1000 * 60 * 60 * 24);
-    set_datetimestruct_days(days, out);
-    out->hour = (int)extract_unit_64(&dt, 1000LL * 1000 * 60 * 60);
-    out->min = (int)extract_unit_64(&dt, 1000LL * 1000 * 60);
-    out->sec = (int)extract_unit_64(&dt, 1000LL * 1000);
-    out->us = (int)dt;
-    break;
-
-  case NPY_FR_ns:
-    days = extract_unit_64(&dt, 1000LL * 1000 * 1000 * 60 * 60 * 24);
-    set_datetimestruct_days(days, out);
-    out->hour = (int)extract_unit_64(&dt, 1000LL * 1000 * 1000 * 60 * 60);
-    out->min = (int)extract_unit_64(&dt, 1000LL * 1000 * 1000 * 60);
-    out->sec = (int)extract_unit_64(&dt, 1000LL * 1000 * 1000);
-    out->us = (int)extract_unit_64(&dt, 1000LL);
-    out->ps = (int)(dt * 1000);
-    break;
-
-  case NPY_FR_ps:
-    days = extract_unit_64(&dt, 1000LL * 1000 * 1000 * 1000 * 60 * 60 * 24);
-    set_datetimestruct_days(days, out);
-    out->hour =
-        (int)extract_unit_64(&dt, 1000LL * 1000 * 1000 * 1000 * 60 * 60);
-    out->min = (int)extract_unit_64(&dt, 1000LL * 1000 * 1000 * 1000 * 60);
-    out->sec = (int)extract_unit_64(&dt, 1000LL * 1000 * 1000 * 1000);
-    out->us = (int)extract_unit_64(&dt, 1000LL * 1000);
-    out->ps = (int)(dt);
-    break;
-
-  case NPY_FR_fs:
-    /* entire range is only +- 2.6 hours */
-    out->hour =
-        (int)extract_unit_64(&dt, 1000LL * 1000 * 1000 * 1000 * 1000 * 60 * 60);
-    if (out->hour < 0) {
-      out->year = 1969;
-      out->month = 12;
-      out->day = 31;
-      out->hour += 24;
-      assert(out->hour >= 0);
-    }
-    out->min =
-        (int)extract_unit_64(&dt, 1000LL * 1000 * 1000 * 1000 * 1000 * 60);
-    out->sec = (int)extract_unit_64(&dt, 1000LL * 1000 * 1000 * 1000 * 1000);
-    out->us = (int)extract_unit_64(&dt, 1000LL * 1000 * 1000);
-    out->ps = (int)extract_unit_64(&dt, 1000LL);
-    out->as = (int)(dt * 1000);
-    break;
-
-  case NPY_FR_as:
-    /* entire range is only +- 9.2 seconds */
-    out->sec =
-        (int)extract_unit_64(&dt, 1000LL * 1000 * 1000 * 1000 * 1000 * 1000);
-    if (out->sec < 0) {
-      out->year = 1969;
-      out->month = 12;
-      out->day = 31;
-      out->hour = 23;
-      out->min = 59;
-      out->sec += 60;
-      assert(out->sec >= 0);
-    }
-    out->us = (int)extract_unit_64(&dt, 1000LL * 1000 * 1000 * 1000);
-    out->ps = (int)extract_unit_64(&dt, 1000LL * 1000);
-    out->as = (int)dt;
-    break;
-
-  default:
-    PyErr_SetString(PyExc_RuntimeError,
-                    "NumPy datetime metadata is corrupted with invalid "
-                    "base unit");
-    return -1;
-  }
-
-  return 0;
-}
diff --git a/src/pantab/numpy_datetime.h b/src/pantab/numpy_datetime.h
deleted file mode 100644
index ef1f1ccf..00000000
--- a/src/pantab/numpy_datetime.h
+++ /dev/null
@@ -1,29 +0,0 @@
-/*
- * This file is derived from NumPy 1.20. See NUMPY_LICENSE.txt
- */
-
-#ifndef _NPY_PRIVATE__DATETIME_H_
-#define _NPY_PRIVATE__DATETIME_H_
-#define NPY_NO_DEPRECATED_API NPY_1_7_API_VERSION
-#include <numpy/ndarraytypes.h>
-
-/*
- * Converts a datetime based on the given metadata into a datetimestruct
- */
-int convert_datetime_to_datetimestruct(PyArray_DatetimeMetaData *meta,
-                                       npy_datetime dt,
-                                       npy_datetimestruct *out);
-
-/*
- * Converts a datetime from a datetimestruct to a datetime based
- * on some metadata. The date is assumed to be valid.
- *
- * TODO: If meta->num is really big, there could be overflow
- *
- * Returns 0 on success, -1 on failure.
- */
-int convert_datetimestruct_to_datetime(PyArray_DatetimeMetaData *meta,
-                                       const npy_datetimestruct *dts,
-                                       npy_datetime *out);
-
-#endif
diff --git a/src/pantab/writer.cpp b/src/pantab/writer.cpp
index b2caf511..f744fc81 100644
--- a/src/pantab/writer.cpp
+++ b/src/pantab/writer.cpp
@@ -6,8 +6,6 @@
 #include <hyperapi/hyperapi.hpp>
 #include <nanoarrow/nanoarrow.hpp>
 
-#include "numpy_datetime.h"
-
 static auto GetHyperTypeFromArrowSchema(struct ArrowSchema *schema,
                                         ArrowError *error)
     -> hyperapi::SqlType {
@@ -270,45 +268,25 @@ class TimestampInsertHelper : public InsertHelper {
            array_view_->buffer_views[1].data.as_uint8 + (idx * elem_size),
            elem_size);
 
-    // using timestamp_t =
-    //    typename std::conditional<TZAware, hyperapi::OffsetTimestamp,
-    //                              hyperapi::Timestamp>::type;
-
     // TODO: need overflow checks here
-    npy_datetimestruct dts;
-    PyArray_DatetimeMetaData meta;
     if constexpr (TU == NANOARROW_TIME_UNIT_SECOND) {
-      meta = {NPY_FR_s, 1};
+      value *= 1000000;
     } else if constexpr (TU == NANOARROW_TIME_UNIT_MILLI) {
-      meta = {NPY_FR_ms, 1};
-    } else if constexpr (TU == NANOARROW_TIME_UNIT_MICRO) {
-      meta = {NPY_FR_us, 1};
+      value *= 1000;
     } else if constexpr (TU == NANOARROW_TIME_UNIT_NANO) {
-      // we assume pandas is ns here but should check format
-      meta = {NPY_FR_ns, 1};
+      value /= 1000;
     }
 
-    int ret = convert_datetime_to_datetimestruct(&meta, value, &dts);
-    if (ret != 0) {
-      throw std::invalid_argument("could not convert datetime value ");
-    }
-    const hyperapi::Date dt{static_cast<int32_t>(dts.year),
-                            static_cast<int16_t>(dts.month),
-                            static_cast<int16_t>(dts.day)};
-    const hyperapi::Time time{static_cast<int8_t>(dts.hour),
-                              static_cast<int8_t>(dts.min),
-                              static_cast<int8_t>(dts.sec), dts.us};
-
-    if constexpr (TZAware) {
-      const hyperapi::OffsetTimestamp ts{dt, time, std::chrono::minutes{0}};
-      hyperapi::internal::ValueInserter{inserter_}.addValue(
-          static_cast<hyperapi::OffsetTimestamp>(ts));
+    constexpr int64_t USEC_TABLEAU_TO_UNIX_EPOCH = 210866803200000000LL;
+    hyper_timestamp_t raw_timestamp =
+        static_cast<hyper_timestamp_t>(value + USEC_TABLEAU_TO_UNIX_EPOCH);
 
-    } else {
-      const hyperapi::Timestamp ts{dt, time};
-      hyperapi::internal::ValueInserter{inserter_}.addValue(
-          static_cast<hyperapi::Timestamp>(ts));
-    }
+    using timestamp_t =
+        typename std::conditional<TZAware, hyperapi::OffsetTimestamp,
+                                  hyperapi::Timestamp>::type;
+    const timestamp_t ts{raw_timestamp, {}};
+    hyperapi::internal::ValueInserter{inserter_}.addValue(
+        static_cast<timestamp_t>(ts));
   }
 };