diff --git a/snap/snapcraft.yaml b/snap/snapcraft.yaml
index 70754e382e..119cbef6e7 100644
--- a/snap/snapcraft.yaml
+++ b/snap/snapcraft.yaml
@@ -171,7 +171,7 @@ parts:
     build-environment:
         # Build PyNaCl from source since the wheel files interact
         # strangely with classic snaps. Well, build it all from source.
-        - "PIP_NO_BINARY": ":all"
+        - "PIP_NO_BINARY": ":all:"
         # Use base image's libsodium for PyNaCl.
         - "SODIUM_INSTALL": "system"
         - "CFLAGS": "$(pkg-config python-3.10 yaml-0.1 --cflags)"