diff --git a/.buildkite/pipeline.yml b/.buildkite/pipeline.yml
index ee2465e71..ef4a06a65 100644
--- a/.buildkite/pipeline.yml
+++ b/.buildkite/pipeline.yml
@@ -53,7 +53,7 @@
             - "1.8"
             - "1.9"
             - "1.10"
-      concurrency: 3
+      concurrency: 1
       concurrency_group: mpi_cuda
       plugins:
         - JuliaCI/julia#v1: