diff --git a/packages/vaex-core/pyproject.toml b/packages/vaex-core/pyproject.toml
index 738855eca..f6663b450 100644
--- a/packages/vaex-core/pyproject.toml
+++ b/packages/vaex-core/pyproject.toml
@@ -6,6 +6,4 @@ requires = [
     # ref https://github.com/scipy/oldest-supported-numpy/pull/86
     "numpy~=2.0",
     "scikit-build",
-    "cmake",
-    "ninja"
 ]
diff --git a/packages/vaex-core/setup.py b/packages/vaex-core/setup.py
index 6931a7e65..6823f5285 100644
--- a/packages/vaex-core/setup.py
+++ b/packages/vaex-core/setup.py
@@ -1,4 +1,5 @@
 from setuptools import setup
+import shutil
 import sys
 import os
 from importlib.machinery import SourceFileLoader
@@ -24,6 +25,11 @@
 version = version.__version__
 url = "https://www.github.com/maartenbreddels/vaex"
 setup_requires = ["numpy~=2.0"] # see vaex-core pyproject.toml
+if use_skbuild:
+    if not shutil.which("cmake"):
+        setup_requires += ["cmake"]
+    if not shutil.which("ninja"):
+        setup_requires += ["ninja"]
 install_requires_core = [
     "aplus",
     "blake3",