diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index beaf3ae03..f6d0096a5 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -87,7 +87,7 @@ jobs:
           create-args: >-
             python
             pip
-            libmambapy
+            libmambapy<2.0
             conda-build
 
       - name: Install dependencies
diff --git a/.github/workflows/ci_win.yml b/.github/workflows/ci_win.yml
index 1a9be527e..0a85ae83c 100644
--- a/.github/workflows/ci_win.yml
+++ b/.github/workflows/ci_win.yml
@@ -56,7 +56,7 @@ jobs:
           create-args: >-
             python
             pip
-            libmambapy
+            libmambapy<2.0
             conda-build
 
       - name: Install dependencies