diff --git a/.ci_support/build_all.py b/.ci_support/build_all.py
index 5ad96239ad552..d7fefc7d067a2 100644
--- a/.ci_support/build_all.py
+++ b/.ci_support/build_all.py
@@ -96,7 +96,7 @@ def build_all(recipes_dir, arch):
         subprocess.run("run_conda_forge_build_setup", shell=True, check=True)
 
     print("Building {} with conda-forge/label/main".format(','.join(folders)))
-    channel_urls = ['local', 'conda-forge', 'defaults']
+    channel_urls = ['local', 'conda-forge']
     build_folders(recipes_dir, folders, arch, channel_urls)
 
 
diff --git a/.ci_support/linux64.yaml b/.ci_support/linux64.yaml
index 7147111977a7c..0babf51a6004c 100644
--- a/.ci_support/linux64.yaml
+++ b/.ci_support/linux64.yaml
@@ -7,7 +7,7 @@ fortran_compiler:
 target_platform:
   - linux-64
 channel_sources:
-  - conda-forge,defaults
+  - conda-forge
 docker_image:
   - quay.io/condaforge/linux-anvil-comp7
 cuda_compiler_version:
diff --git a/.ci_support/osx64.yaml b/.ci_support/osx64.yaml
index 1a9e1e084694d..0b7e1f30ef0da 100644
--- a/.ci_support/osx64.yaml
+++ b/.ci_support/osx64.yaml
@@ -5,6 +5,6 @@ cxx_compiler:
 fortran_compiler:
   - gfortran
 channel_sources:
-  - conda-forge,defaults
+  - conda-forge
 target_platform:
   - osx-64
diff --git a/.ci_support/win64.yaml b/.ci_support/win64.yaml
index 47d25abeebaaf..dfb5b8c1a89bf 100644
--- a/.ci_support/win64.yaml
+++ b/.ci_support/win64.yaml
@@ -1,4 +1,4 @@
 channel_sources:
-  - conda-forge,defaults
+  - conda-forge
 target_platform:
   - win-64
diff --git a/.scripts/build_steps.sh b/.scripts/build_steps.sh
index 551a622dd0b44..44f8965ef270c 100755
--- a/.scripts/build_steps.sh
+++ b/.scripts/build_steps.sh
@@ -12,7 +12,6 @@ cat >~/.condarc <<CONDARC
 
 channels:
  - conda-forge
- - defaults
 
 conda-build:
  root-dir: /home/conda/staged-recipes/build_artifacts