diff --git a/.github/workflows/acceptance-tests.yml b/.github/workflows/acceptance-tests.yml
index 66139061c..9acfada38 100644
--- a/.github/workflows/acceptance-tests.yml
+++ b/.github/workflows/acceptance-tests.yml
@@ -7,7 +7,7 @@ permissions: {}
 
 jobs:
   acceptance-tests:
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-26.04
     steps:
       - name: Check out
         with:
diff --git a/.github/workflows/api-diff.yml b/.github/workflows/api-diff.yml
index b4553caad..e84105db0 100644
--- a/.github/workflows/api-diff.yml
+++ b/.github/workflows/api-diff.yml
@@ -22,7 +22,7 @@ permissions:
 jobs:
   api-diff:
     if: ${{ !startsWith(github.head_ref, 'release-please--branches--') }}
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-26.04
     env:
       # Empty unless overridden via workflow_dispatch; the api-diff task then
       # falls back to <api.diff.baseline.version> in pom.xml.
diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 3d0042b3e..762debad1 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -7,7 +7,7 @@ permissions: {}
 
 jobs:
   build:
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-26.04
     steps:
       - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7
         with:
diff --git a/.github/workflows/bump-api-diff-baseline.yml b/.github/workflows/bump-api-diff-baseline.yml
index 36ef86c23..87b465f75 100644
--- a/.github/workflows/bump-api-diff-baseline.yml
+++ b/.github/workflows/bump-api-diff-baseline.yml
@@ -25,7 +25,7 @@ env:
 
 jobs:
   bump:
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-26.04
     permissions:
       contents: write # push to the snapshot PR branch
     steps:
diff --git a/.github/workflows/codeql.yml b/.github/workflows/codeql.yml
index 5537cf6f2..016333661 100644
--- a/.github/workflows/codeql.yml
+++ b/.github/workflows/codeql.yml
@@ -14,7 +14,7 @@ permissions: {}
 jobs:
   analyze:
     name: Analyze Java
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-26.04
     permissions:
       actions: read # required for github/codeql-action/init to get workflow details
       contents: read
diff --git a/.github/workflows/detect-api-changes.yml b/.github/workflows/detect-api-changes.yml
index f0de28c7a..030af0bbb 100644
--- a/.github/workflows/detect-api-changes.yml
+++ b/.github/workflows/detect-api-changes.yml
@@ -18,7 +18,7 @@ permissions: {}
 jobs:
   detect-api-changes:
     if: github.repository == 'prometheus/client_java'
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-26.04
     permissions:
       issues: write
       pull-requests: write
diff --git a/.github/workflows/generate-protobuf.yml b/.github/workflows/generate-protobuf.yml
index 139cef983..04fa26670 100644
--- a/.github/workflows/generate-protobuf.yml
+++ b/.github/workflows/generate-protobuf.yml
@@ -10,7 +10,7 @@ permissions: {}
 
 jobs:
   generate:
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-26.04
     permissions:
       contents: read # checkout + read-only `git fetch origin main` for the verify step
     steps:
@@ -63,7 +63,7 @@ jobs:
           retention-days: 5
 
   publish:
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-26.04
     needs: generate
     permissions:
       contents: write # push regenerated sources back to the renovate branch
diff --git a/.github/workflows/github-pages.yaml b/.github/workflows/github-pages.yaml
index 281e4047a..73367caad 100644
--- a/.github/workflows/github-pages.yaml
+++ b/.github/workflows/github-pages.yaml
@@ -30,7 +30,7 @@ jobs:
   # Build job
   build:
     if: github.repository == 'prometheus/client_java'
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-26.04
     steps:
       - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7
         with:
@@ -65,7 +65,7 @@ jobs:
     environment:
       name: github-pages
       url: ${{ steps.deployment.outputs.page_url }}
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-26.04
     needs: build
     steps:
       - name: Deploy to GitHub Pages
diff --git a/.github/workflows/java-version-matrix-tests.yml b/.github/workflows/java-version-matrix-tests.yml
index 0dcbdc64b..38ed46315 100644
--- a/.github/workflows/java-version-matrix-tests.yml
+++ b/.github/workflows/java-version-matrix-tests.yml
@@ -19,7 +19,7 @@ permissions: {}
 jobs:
   integration-tests:
     name: Java ${{ matrix.java-version }}
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-26.04
     strategy:
       fail-fast: false
       matrix:
diff --git a/.github/workflows/jmx-exporter-compatibility.yml b/.github/workflows/jmx-exporter-compatibility.yml
index 330fb0aba..725d2e2fa 100644
--- a/.github/workflows/jmx-exporter-compatibility.yml
+++ b/.github/workflows/jmx-exporter-compatibility.yml
@@ -17,7 +17,7 @@ permissions: {}
 
 jobs:
   jmx-exporter-compatibility:
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-26.04
     steps:
       - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7
         with:
diff --git a/.github/workflows/lint.yml b/.github/workflows/lint.yml
index 70762dde7..23096be67 100644
--- a/.github/workflows/lint.yml
+++ b/.github/workflows/lint.yml
@@ -8,7 +8,7 @@ permissions: {}
 
 jobs:
   lint:
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-26.04
 
     permissions:
       contents: read
diff --git a/.github/workflows/micrometer-compatibility.yml b/.github/workflows/micrometer-compatibility.yml
index bdc625157..18caf704a 100644
--- a/.github/workflows/micrometer-compatibility.yml
+++ b/.github/workflows/micrometer-compatibility.yml
@@ -10,7 +10,7 @@ permissions: {}
 jobs:
   compat-test:
     name: ${{ matrix.name }}
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-26.04
     strategy:
       fail-fast: false
       matrix:
@@ -47,7 +47,7 @@ jobs:
 
   micrometer-compatibility:
     name: micrometer-compatibility
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-26.04
     needs: compat-test
     if: always()
     steps:
diff --git a/.github/workflows/multi-version-test.yml b/.github/workflows/multi-version-test.yml
index 1037e7a3d..bd0a7e063 100644
--- a/.github/workflows/multi-version-test.yml
+++ b/.github/workflows/multi-version-test.yml
@@ -8,7 +8,7 @@ permissions: {}
 jobs:
   compatibility-test:
     name: Test on Java ${{ matrix.java }}
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-26.04
     strategy:
       fail-fast: false
       matrix:
diff --git a/.github/workflows/native-tests.yml b/.github/workflows/native-tests.yml
index e04b74c2d..d1fe2c838 100644
--- a/.github/workflows/native-tests.yml
+++ b/.github/workflows/native-tests.yml
@@ -7,7 +7,7 @@ permissions: {}
 
 jobs:
   native-tests:
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-26.04
     steps:
       - name: Check out
         with:
diff --git a/.github/workflows/nightly-benchmarks.yml b/.github/workflows/nightly-benchmarks.yml
index cd0179d18..7f10ef3a4 100644
--- a/.github/workflows/nightly-benchmarks.yml
+++ b/.github/workflows/nightly-benchmarks.yml
@@ -23,7 +23,7 @@ defaults:
 
 jobs:
   benchmark:
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-26.04
     permissions:
       contents: read # checkout only
     steps:
@@ -69,7 +69,7 @@ jobs:
           retention-days: 5
 
   publish:
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-26.04
     needs: benchmark
     permissions:
       contents: write # push generated results to the benchmarks branch
diff --git a/.github/workflows/pr-benchmark-report.yml b/.github/workflows/pr-benchmark-report.yml
index 6a9a1c1e9..41af4151f 100644
--- a/.github/workflows/pr-benchmark-report.yml
+++ b/.github/workflows/pr-benchmark-report.yml
@@ -18,7 +18,7 @@ jobs:
       github.event.workflow_run.event == 'pull_request' &&
       github.event.workflow_run.conclusion != 'cancelled' &&
       github.event.workflow_run.conclusion != 'skipped'
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-26.04
     permissions:
       actions: read
       contents: read
diff --git a/.github/workflows/pr-benchmarks.yml b/.github/workflows/pr-benchmarks.yml
index d96424f76..a5883b059 100644
--- a/.github/workflows/pr-benchmarks.yml
+++ b/.github/workflows/pr-benchmarks.yml
@@ -18,7 +18,7 @@ defaults:
 jobs:
   benchmark:
     if: github.event.label.name == 'benchmark'
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-26.04
     strategy:
       fail-fast: false
       matrix:
@@ -101,7 +101,7 @@ jobs:
 
   summarize:
     if: github.event.label.name == 'benchmark'
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-26.04
     needs: benchmark
     permissions:
       contents: read # checkout only
diff --git a/.github/workflows/regenerate-api-diff-otel.yml b/.github/workflows/regenerate-api-diff-otel.yml
index 9366fbee3..d13157fe0 100644
--- a/.github/workflows/regenerate-api-diff-otel.yml
+++ b/.github/workflows/regenerate-api-diff-otel.yml
@@ -10,7 +10,7 @@ permissions: {}
 
 jobs:
   generate:
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-26.04
     permissions:
       contents: read # checkout + read-only `git fetch origin main` for the verify step
     steps:
@@ -56,7 +56,7 @@ jobs:
           retention-days: 5
 
   publish:
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-26.04
     needs: generate
     permissions:
       contents: write # push regenerated apidiffs back to the renovate branch
diff --git a/.github/workflows/release-please.yml b/.github/workflows/release-please.yml
index 9e2b1cf62..909bc891b 100644
--- a/.github/workflows/release-please.yml
+++ b/.github/workflows/release-please.yml
@@ -11,7 +11,7 @@ permissions: {}
 jobs:
   release-please:
     if: ${{ github.repository == 'prometheus/client_java' }}
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-26.04
     permissions:
       contents: write # release-please creates release commits, tags, and the GitHub release
       pull-requests: write # release-please opens/updates the release PR
diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index a6f8dee9e..92990c7f2 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -14,7 +14,7 @@ jobs:
   deploy:
     if: ${{ github.repository == 'prometheus/client_java' }}
     environment: release
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-26.04
     env:
       # Artifact releases pair a focused tool allowlist with cache: false.
       MISE_ENABLE_TOOLS: java
diff --git a/.github/workflows/scorecard.yml b/.github/workflows/scorecard.yml
index 0551cef90..bb712f39e 100644
--- a/.github/workflows/scorecard.yml
+++ b/.github/workflows/scorecard.yml
@@ -13,7 +13,7 @@ permissions: {}
 jobs:
   analysis:
     name: Scorecard analysis
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-26.04
     # Prevents fork runs from failing due to missing write permissions or secrets.
     if: ${{ github.repository == 'prometheus/client_java' }}
     permissions:
diff --git a/.github/workflows/test-release-build.yml b/.github/workflows/test-release-build.yml
index cbc751432..c99d45b7f 100644
--- a/.github/workflows/test-release-build.yml
+++ b/.github/workflows/test-release-build.yml
@@ -11,7 +11,7 @@ permissions: {}
 
 jobs:
   build:
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-26.04
     steps:
       - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7
         with: