diff --git a/.circleci/config.yml b/.circleci/config.yml
index 92ae4e0d..1a67d4e1 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -18,7 +18,7 @@ commands:
           name: Setup Rust checks
           command: |
             rustup component add rustfmt
-            cargo install cargo-audit
+            cargo install --locked cargo-audit
             rustup component add clippy
   setup-python:
     steps:
@@ -140,7 +140,7 @@ commands:
       - run:
           name: Install sccache
           command: |
-            cargo install sccache
+            cargo install --locked sccache
             # This configures Rust to use sccache.
             echo 'export "RUSTC_WRAPPER"="sccache"' >> $BASH_ENV
             # This is the maximum space sccache cache will use on disk.