diff --git a/docs/src/whatsnew/latest.rst b/docs/src/whatsnew/latest.rst
index 9564863d1b..58d94bf5fa 100644
--- a/docs/src/whatsnew/latest.rst
+++ b/docs/src/whatsnew/latest.rst
@@ -66,7 +66,8 @@ This document explains the changes made to Iris for this release
 🔗 Dependencies
 ===============
 
-#. N/A
+#. `@bjlittle`_ enforced the minimum pin of ``numpy>1.21`` in accordance with the `NEP29 Drop Schedule`_.
+   (:pull:`5525`)
 
 
 📚 Documentation
@@ -117,3 +118,6 @@ This document explains the changes made to Iris for this release
 
 .. comment
     Whatsnew resources in alphabetical order:
+
+.. _NEP29 Drop Schedule: https://numpy.org/neps/nep-0029-deprecation_policy.html#drop-schedule
+
diff --git a/requirements/py310.yml b/requirements/py310.yml
index fd549a9cf7..b01586aac9 100644
--- a/requirements/py310.yml
+++ b/requirements/py310.yml
@@ -18,7 +18,7 @@ dependencies:
   - libnetcdf !=4.9.1
   - matplotlib >=3.5
   - netcdf4
-  - numpy >=1.21, !=1.24.3
+  - numpy >1.21, !=1.24.3
   - python-xxhash
   - pyproj
   - scipy
diff --git a/requirements/py311.yml b/requirements/py311.yml
index a883e5d87a..286fe74a33 100644
--- a/requirements/py311.yml
+++ b/requirements/py311.yml
@@ -18,7 +18,7 @@ dependencies:
   - libnetcdf !=4.9.1
   - matplotlib >=3.5
   - netcdf4
-  - numpy >=1.21, !=1.24.3
+  - numpy >1.21, !=1.24.3
   - python-xxhash
   - pyproj
   - scipy
diff --git a/requirements/py39.yml b/requirements/py39.yml
index 5b3c17510e..f534aef4f3 100644
--- a/requirements/py39.yml
+++ b/requirements/py39.yml
@@ -18,7 +18,7 @@ dependencies:
   - libnetcdf !=4.9.1
   - matplotlib >=3.5
   - netcdf4
-  - numpy >=1.21, !=1.24.3
+  - numpy >1.21, !=1.24.3
   - python-xxhash
   - pyproj
   - scipy
diff --git a/requirements/pypi-core.txt b/requirements/pypi-core.txt
index 7937f73b4f..e286bb97bc 100644
--- a/requirements/pypi-core.txt
+++ b/requirements/pypi-core.txt
@@ -5,8 +5,8 @@ dask[array]>=2022.9.0
 # libnetcdf!=4.9.1 (not available on PyPI)
 matplotlib>=3.5
 netcdf4
-numpy>=1.21,!=1.24.3
+numpy>1.21,!=1.24.3
 pyproj
 scipy
 shapely!=1.8.3
-xxhash
\ No newline at end of file
+xxhash