diff --git a/.ci-builds/.azure-exhaustive-tests.yml b/.ci-builds/.azure-exhaustive-tests.yml
index 6d1cb52b8b9..92b3b7d6567 100644
--- a/.ci-builds/.azure-exhaustive-tests.yml
+++ b/.ci-builds/.azure-exhaustive-tests.yml
@@ -7,6 +7,10 @@
 # also batch up any pending changes so that we will only have at most
 # one build running at a given time (since they take a long time).
 trigger:
+  # batch=true to reduce number of concurrent runs on the same branch:
+  # https://learn.microsoft.com/en-us/azure/devops/pipelines/yaml-schema/trigger?view=azure-pipelines#properties
+  # potential future feature to supersede batch=true:
+  # https://learn.microsoft.com/en-us/azure/devops/pipelines/process/stages?view=azure-devops&tabs=yaml#specify-queuing-policies
   batch: true
   branches:
     include:
diff --git a/.ci-builds/.azure-pipelines-icu4c.yml b/.ci-builds/.azure-pipelines-icu4c.yml
index ef1cdb33d22..2c7e675aa0c 100644
--- a/.ci-builds/.azure-pipelines-icu4c.yml
+++ b/.ci-builds/.azure-pipelines-icu4c.yml
@@ -1,6 +1,11 @@
 # Azure Pipelines (VSTS) configuration for CI builds for ICU.
 
 trigger:
+  # batch=true to reduce number of concurrent runs on the same branch:
+  # https://learn.microsoft.com/en-us/azure/devops/pipelines/yaml-schema/trigger?view=azure-pipelines#properties
+  # potential future feature to supersede batch=true:
+  # https://learn.microsoft.com/en-us/azure/devops/pipelines/process/stages?view=azure-devops&tabs=yaml#specify-queuing-policies
+  batch: true
   branches:
     include:
     - main
diff --git a/.ci-builds/.azure-pipelines-icu4j.yml b/.ci-builds/.azure-pipelines-icu4j.yml
index a2d7f7cb01a..f841b49cc79 100644
--- a/.ci-builds/.azure-pipelines-icu4j.yml
+++ b/.ci-builds/.azure-pipelines-icu4j.yml
@@ -1,6 +1,11 @@
 # Azure Pipelines (VSTS) configuration for CI builds for ICU.
 
 trigger:
+  # batch=true to reduce number of concurrent runs on the same branch:
+  # https://learn.microsoft.com/en-us/azure/devops/pipelines/yaml-schema/trigger?view=azure-pipelines#properties
+  # potential future feature to supersede batch=true:
+  # https://learn.microsoft.com/en-us/azure/devops/pipelines/process/stages?view=azure-devops&tabs=yaml#specify-queuing-policies
+  batch: true
   branches:
     include:
     - main
diff --git a/.ci-builds/.azure-post-merge-tests.yml b/.ci-builds/.azure-post-merge-tests.yml
index 121fa011aeb..f7f21903b88 100644
--- a/.ci-builds/.azure-post-merge-tests.yml
+++ b/.ci-builds/.azure-post-merge-tests.yml
@@ -1,5 +1,10 @@
 # Azure Pipelines (VSTS) configuration for testing things post merging
 trigger:
+  # batch=true to reduce number of concurrent runs on the same branch:
+  # https://learn.microsoft.com/en-us/azure/devops/pipelines/yaml-schema/trigger?view=azure-pipelines#properties
+  # potential future feature to supersede batch=true:
+  # https://learn.microsoft.com/en-us/azure/devops/pipelines/process/stages?view=azure-devops&tabs=yaml#specify-queuing-policies
+  batch: true
   branches:
     include:
     - main
diff --git a/.github/workflows/icu4c.yml b/.github/workflows/icu4c.yml
index 3509ccdb65f..f635964826b 100644
--- a/.github/workflows/icu4c.yml
+++ b/.github/workflows/icu4c.yml
@@ -22,6 +22,13 @@ on:
     # To trigger the Env Test workflow manually, follow the instructions in
     # https://docs.github.com/en/actions/managing-workflow-runs/manually-running-a-workflow
 
+# For non-release branches (namely: PRs), only run CI on the most recent commit. Cancel
+# runs on previous commits mid-flight when new commits are pushed.
+# https://docs.github.com/en/actions/using-jobs/using-concurrency#example-only-cancel-in-progress-jobs-on-specific-branches
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: ${{ !contains(github.ref, 'maint/') && github.ref != 'main' }}
+
 permissions:
   contents: read
 
diff --git a/.github/workflows/icu4j.yml b/.github/workflows/icu4j.yml
index 63edb8b3ab6..28baf7920fa 100644
--- a/.github/workflows/icu4j.yml
+++ b/.github/workflows/icu4j.yml
@@ -22,6 +22,13 @@ on:
     # To trigger the Env Test workflow manually, follow the instructions in
     # https://docs.github.com/en/actions/managing-workflow-runs/manually-running-a-workflow
 
+# For non-release branches (namely: PRs), only run CI on the most recent commit. Cancel
+# runs on previous commits mid-flight when new commits are pushed.
+# https://docs.github.com/en/actions/using-jobs/using-concurrency#example-only-cancel-in-progress-jobs-on-specific-branches
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: ${{ !contains(github.ref, 'maint/') && github.ref != 'main' }}
+
 env:
   SHARED_MVN_ARGS: '--show-version --no-transfer-progress'
 
diff --git a/.github/workflows/icu_common.yml b/.github/workflows/icu_common.yml
index ccbcfc1aaec..2b9c1d86c5c 100644
--- a/.github/workflows/icu_common.yml
+++ b/.github/workflows/icu_common.yml
@@ -16,6 +16,13 @@ on:
     # To trigger the Env Test workflow manually, follow the instructions in
     # https://docs.github.com/en/actions/managing-workflow-runs/manually-running-a-workflow
 
+# For non-release branches (namely: PRs), only run CI on the most recent commit. Cancel
+# runs on previous commits mid-flight when new commits are pushed.
+# https://docs.github.com/en/actions/using-jobs/using-concurrency#example-only-cancel-in-progress-jobs-on-specific-branches
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: ${{ !contains(github.ref, 'maint/') && github.ref != 'main' }}
+
 env:
   SHARED_MVN_ARGS: '--show-version --no-transfer-progress'
 
diff --git a/.github/workflows/icu_docs.yml b/.github/workflows/icu_docs.yml
index 1a5a82a3875..239ee4afb8d 100644
--- a/.github/workflows/icu_docs.yml
+++ b/.github/workflows/icu_docs.yml
@@ -22,6 +22,13 @@ on:
     # To trigger the Env Test workflow manually, follow the instructions in
     # https://docs.github.com/en/actions/managing-workflow-runs/manually-running-a-workflow
 
+# For non-release branches (namely: PRs), only run CI on the most recent commit. Cancel
+# runs on previous commits mid-flight when new commits are pushed.
+# https://docs.github.com/en/actions/using-jobs/using-concurrency#example-only-cancel-in-progress-jobs-on-specific-branches
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: ${{ !contains(github.ref, 'maint/') && github.ref != 'main' }}
+
 permissions:
   contents: read
 
diff --git a/.github/workflows/icu_merge_ci.yml b/.github/workflows/icu_merge_ci.yml
index 40195aa0ceb..23b2d5315bc 100644
--- a/.github/workflows/icu_merge_ci.yml
+++ b/.github/workflows/icu_merge_ci.yml
@@ -14,6 +14,13 @@ on:
     # To trigger the Env Test workflow manually, follow the instructions in
     # https://docs.github.com/en/actions/managing-workflow-runs/manually-running-a-workflow
 
+# For non-release branches (namely: PRs), only run CI on the most recent commit. Cancel
+# runs on previous commits mid-flight when new commits are pushed.
+# https://docs.github.com/en/actions/using-jobs/using-concurrency#example-only-cancel-in-progress-jobs-on-specific-branches
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: ${{ !contains(github.ref, 'maint/') && github.ref != 'main' }}
+
 env:
   SHARED_MVN_ARGS: '--show-version --no-transfer-progress'
 
diff --git a/.github/workflows/icu_valgrind.yml b/.github/workflows/icu_valgrind.yml
index c57004b0c02..7128e1fc617 100644
--- a/.github/workflows/icu_valgrind.yml
+++ b/.github/workflows/icu_valgrind.yml
@@ -20,6 +20,13 @@ on:
       - 'icu4c/**'
       - '.github/workflows/**'
 
+# For non-release branches (namely: PRs), only run CI on the most recent commit. Cancel
+# runs on previous commits mid-flight when new commits are pushed.
+# https://docs.github.com/en/actions/using-jobs/using-concurrency#example-only-cancel-in-progress-jobs-on-specific-branches
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: ${{ !contains(github.ref, 'maint/') && github.ref != 'main' }}
+
 permissions:
   contents: read