diff --git a/scripts/prepare-fnos-dependencies.sh b/scripts/prepare-fnos-dependencies.sh
index 69ac7bb..7357144 100755
--- a/scripts/prepare-fnos-dependencies.sh
+++ b/scripts/prepare-fnos-dependencies.sh
@@ -5,6 +5,8 @@ ROOT_DIR=$(CDPATH= cd -- "$(dirname -- "$0")/.." && pwd)
 PYTHON_BIN=${PYTHON:-python3}
 WHEELHOUSE=${IMAGEFIND_WHEEL_CACHE:-$ROOT_DIR/.fnos-wheel-cache/python312}
 DOWNLOAD_ROOT=${IMAGEFIND_DEPENDENCY_TMPDIR:-${TMPDIR:-/tmp}}
+PIP_INDEX_URL=${PIP_INDEX_URL:-https://pypi.tuna.tsinghua.edu.cn/simple}
+PIP_TIMEOUT=${PIP_TIMEOUT:-60}
 OPENCL_URL=https://deb.debian.org/debian/pool/main/o/ocl-icd/ocl-icd-libopencl1_2.2.14-2_amd64.deb
 OPENCL_SHA256=f3367b78f2548e6211e23081b3e0f144babfcc906c5bdbbe0d5e41915de70128
 
@@ -13,6 +15,7 @@ for command_name in curl dpkg-deb find install sha256sum; do command -v "$comman
 mkdir -p "$WHEELHOUSE" "$ROOT_DIR/vendor" "$DOWNLOAD_ROOT"
 
 "$PYTHON_BIN" -m pip download --disable-pip-version-check --only-binary=:all: \
+    --index-url "$PIP_INDEX_URL" --timeout "$PIP_TIMEOUT" --retries 4 \
     --implementation cp --python-version 312 --abi cp312 \
     --platform manylinux_2_28_x86_64 --platform manylinux_2_27_x86_64 \
     --platform manylinux2014_x86_64 --platform manylinux2010_x86_64 --platform manylinux1_x86_64 \
diff --git a/tests/test_fnos_dependency_script.py b/tests/test_fnos_dependency_script.py
new file mode 100644
index 0000000..09ab4e2
--- /dev/null
+++ b/tests/test_fnos_dependency_script.py
@@ -0,0 +1,8 @@
+from pathlib import Path
+
+
+def test_fnos_dependency_download_uses_fast_configurable_index() -> None:
+    script = (Path(__file__).parents[1] / "scripts" / "prepare-fnos-dependencies.sh").read_text()
+    assert "PIP_INDEX_URL=${PIP_INDEX_URL:-https://pypi.tuna.tsinghua.edu.cn/simple}" in script
+    assert '--index-url "$PIP_INDEX_URL"' in script
+    assert '--timeout "$PIP_TIMEOUT" --retries 4' in script