diff --git a/.github/actions/cache_swiftpm_build/action.yml b/.github/actions/cache_swiftpm_build/action.yml
new file mode 100644
index 000000000..3488c5129
--- /dev/null
+++ b/.github/actions/cache_swiftpm_build/action.yml
@@ -0,0 +1,35 @@
+name: 'Cache SwiftPM .build'
+description: |
+  Restore/save a SwiftPM .build directory keyed on Swift version, OS, a
+  job-specific tag, and a hash of the relevant package + source files.
+  Falls back to the most recent cache for the same job tag so SwiftPM
+  performs incremental compilation when sources change.
+
+inputs:
+  path:
+    description: 'Path to the .build directory to cache (e.g. .build, Benchmarks/.build)'
+    required: true
+  tag:
+    description: 'Short job-specific tag, used to keep different jobs from sharing caches'
+    required: true
+  hash-files:
+    description: 'Newline-separated glob patterns hashed into the cache key'
+    required: true
+  swift-version:
+    description: 'Swift version, used as part of the cache key (defaults to matrix.swift_version)'
+    required: true
+  os-version:
+    description: 'OS version, used as part of the cache key (defaults to matrix.os_version)'
+    required: true
+
+runs:
+  using: composite
+  steps:
+    - name: Cache ${{ inputs.path }}
+      uses: actions/cache@v5
+      continue-on-error: true
+      with:
+        path: ${{ inputs.path }}
+        key: ${{ runner.os }}-swift${{ inputs.swift-version }}-${{ inputs.os-version }}-build-${{ inputs.tag }}-${{ hashFiles(inputs.hash-files) }}
+        restore-keys: |
+          ${{ runner.os }}-swift${{ inputs.swift-version }}-${{ inputs.os-version }}-build-${{ inputs.tag }}-
diff --git a/.github/actions/prepare_env/action.yml b/.github/actions/prepare_env/action.yml
index 90854db0b..8858a518d 100644
--- a/.github/actions/prepare_env/action.yml
+++ b/.github/actions/prepare_env/action.yml
@@ -32,7 +32,7 @@ runs:
       #  shell: bash
       #  run: ./gradlew -q javaToolchains
     - name: Cache local SwiftPM repository
-      if: matrix.os_version == 'jammy'
+      if: matrix.os_version == 'noble'
       uses: actions/cache@v4
       continue-on-error: true
       with:
diff --git a/.github/workflows/pull_request.yml b/.github/workflows/pull_request.yml
index 3348d06bb..a8f8c228d 100644
--- a/.github/workflows/pull_request.yml
+++ b/.github/workflows/pull_request.yml
@@ -34,14 +34,26 @@ jobs:
       fail-fast: true
       matrix:
         swift_version: ['6.3']
-        os_version: ['jammy']
+        os_version: ['noble']
         jdk_vendor: ['corretto']
     steps:
       - uses: actions/checkout@v6
       - name: Prepare CI Environment
         uses: ./.github/actions/prepare_env
+      - name: Cache .build
+        uses: ./.github/actions/cache_swiftpm_build
+        with:
+          path: .build
+          tag: docs
+          swift-version: ${{ matrix.swift_version }}
+          os-version: ${{ matrix.os_version }}
+          hash-files: |
+            Package.swift
+            Package.resolved
+            Sources/**/*.swift
+            Plugins/**/*.swift
       - name: Swift Build
-        run: swift build --disable-experimental-prebuilts  # FIXME: until prebuilt swift-syntax isn't broken on 6.2 anymore: https://github.com/swiftlang/swift-java/issues/418
+        run: swift build
       - name: Run documentation check
         run: ./.github/scripts/validate_docs.sh
 
@@ -54,7 +66,7 @@ jobs:
       fail-fast: true
       matrix:
         swift_version: ['6.3', 'nightly']
-        os_version: ['jammy']
+        os_version: ['noble']
         jdk_vendor: ['corretto']
     container:
       image: ${{ (contains(matrix.swift_version, 'nightly') && 'swiftlang/swift') || 'swift' }}:${{ matrix.swift_version }}-${{ matrix.os_version }}
@@ -104,7 +116,7 @@ jobs:
       fail-fast: true
       matrix:
         swift_version: ['6.3']
-        os_version: ['jammy']
+        os_version: ['noble']
         jdk_vendor: ['corretto']
     container:
       image: ${{ (contains(matrix.swift_version, 'nightly') && 'swiftlang/swift') || 'swift' }}:${{ matrix.swift_version }}-${{ matrix.os_version }}
@@ -124,7 +136,7 @@ jobs:
       fail-fast: true
       matrix:
         swift_version: ['6.3']
-        os_version: ['jammy']
+        os_version: ['noble']
         jdk_vendor: ['corretto']
     container:
       image: ${{ (contains(matrix.swift_version, 'nightly') && 'swiftlang/swift') || 'swift' }}:${{ matrix.swift_version }}-${{ matrix.os_version }}
@@ -136,8 +148,20 @@ jobs:
         uses: ./.github/actions/prepare_env
       - name: Install jemalloc
         run: apt-get update && apt-get install -y libjemalloc-dev
+      - name: Cache Benchmarks/.build
+        uses: ./.github/actions/cache_swiftpm_build
+        with:
+          path: Benchmarks/.build
+          tag: benchmarks
+          swift-version: ${{ matrix.swift_version }}
+          os-version: ${{ matrix.os_version }}
+          hash-files: |
+            Benchmarks/Package.swift
+            Benchmarks/Package.resolved
+            Benchmarks/Benchmarks/**/*.swift
+            Benchmarks/Sources/**/*.swift
       - name: Swift Benchmarks
-        run: swift package --package-path Benchmarks/ --disable-experimental-prebuilts benchmark  # FIXME: until prebuilt swift-syntax isn't broken on 6.2 anymore: https://github.com/swiftlang/swift-java/issues/418
+        run: swift package --package-path Benchmarks/ benchmark
 
   test-swift:
     name: Test (Swift) (${{ matrix.os_version }} swift:${{ matrix.swift_version }} jdk:${{matrix.jdk_vendor}})
@@ -148,7 +172,7 @@ jobs:
       fail-fast: false
       matrix:
         swift_version: ['6.1.3', '6.3', 'nightly']
-        os_version: ['jammy']
+        os_version: ['noble']
         jdk_vendor: ['corretto']
     container:
       image: ${{ (contains(matrix.swift_version, 'nightly') && 'swiftlang/swift') || 'swift' }}:${{ matrix.swift_version }}-${{ matrix.os_version }}
@@ -158,6 +182,19 @@ jobs:
       - uses: actions/checkout@v6
       - name: Prepare CI Environment
         uses: ./.github/actions/prepare_env
+      - name: Cache .build
+        uses: ./.github/actions/cache_swiftpm_build
+        with:
+          path: .build
+          tag: test
+          swift-version: ${{ matrix.swift_version }}
+          os-version: ${{ matrix.os_version }}
+          hash-files: |
+            Package.swift
+            Package.resolved
+            Sources/**/*.swift
+            Plugins/**/*.swift
+            Tests/**/*.swift
       - name: Swift Build
         run: swift build --build-tests --disable-sandbox --disable-experimental-prebuilts  # FIXME: until prebuilt swift-syntax isn't broken on 6.2 anymore: https://github.com/swiftlang/swift-java/issues/418
       - name: Swift Test (XCTest)
@@ -200,7 +237,7 @@ jobs:
       fail-fast: false
       matrix:
         swift_version: ['6.3']
-        os_version: ['jammy']
+        os_version: ['noble']
         jdk_vendor: ['corretto']
         sdk_triple: ['aarch64-unknown-linux-android28', 'x86_64-unknown-linux-android28', 'armv7-unknown-linux-android28']
         ndk_version: ['r27d', 'r28c']
@@ -226,7 +263,7 @@ jobs:
       fail-fast: false
       matrix:
         swift_version: ['6.3']
-        os_version: ['jammy']
+        os_version: ['noble']
         jdk_vendor: ['corretto']
         sample_app: [  # TODO: use a reusable-workflow to generate those names
           'JavaDependencySampleApp',
@@ -295,18 +332,29 @@ jobs:
         run: .github/scripts/validate_sample.sh Samples/${{ matrix.sample_app }}
 
   linkage-test:
-    name: Linkage test (jammy swift:6.3)
+    name: Linkage test (noble swift:6.3)
     runs-on: ubuntu-latest
     strategy:
       fail-fast: false
       matrix:
         jdk_vendor: ['corretto']
     container:
-      image: swift:6.3-jammy
+      image: swift:6.3-noble
     steps:
       - uses: actions/checkout@v6
       - name: Prepare CI Environment
         uses: ./.github/actions/prepare_env
+      - name: Cache Tests/LinkageTest/.build
+        uses: ./.github/actions/cache_swiftpm_build
+        with:
+          path: Tests/LinkageTest/.build
+          tag: linkage
+          swift-version: '6.3'
+          os-version: noble
+          hash-files: |
+            Tests/LinkageTest/Package.swift
+            Tests/LinkageTest/Package.resolved
+            Tests/LinkageTest/Sources/**/*.swift
       - name: Run linkage test
         run: ./scripts/run-linkage-test.sh
         env:
@@ -320,13 +368,26 @@ jobs:
       matrix:
         jdk_vendor: ['corretto']
     container:
-      image: swift:6.3-jammy
+      image: swift:6.3-noble
     steps:
       - uses: actions/checkout@v6
       - name: Mark workspace as safe for git
         run: git config --global --add safe.directory "$GITHUB_WORKSPACE"
       - name: Prepare CI Environment
         uses: ./.github/actions/prepare_env
+      - name: Cache .build
+        uses: ./.github/actions/cache_swiftpm_build
+        with:
+          path: .build
+          tag: wrapjava
+          swift-version: '6.3'
+          os-version: noble
+          hash-files: |
+            Package.swift
+            Package.resolved
+            Sources/SwiftJavaTool/**/*.swift
+            Sources/SwiftJavaToolLib/**/*.swift
+            Sources/SwiftJava/**/*.swift
       - name: Regenerate JavaStdlib wrappers
         env:
           JAVA_HOME: ${{ env.JAVA_HOME_25 }}