diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 0000000..08daf2d
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,183 @@
+name: CI
+on:
+  pull_request:
+    paths:
+      # We only want to run CI on spack versions that don't utilise symlinks (AKA pre-v1.1),
+      # in order to keep the CI simple. This means that the below pattern is essentially
+      # everthing in the v* directories, excluding the symlinked v0.* spack versions.
+      - 'v**'
+      - '!v0.**'
+  workflow_dispatch:
+    inputs:
+      spack-config-directories-to-test:
+        description: 'Space-separated list of version-based spack-config directories to test against'
+        required: true
+        type: string
+        default: v1.1
+      spack-config-ref:
+        description: 'spack-config ref to use'
+        required: true
+        type: string
+      spack-ref:
+        description: 'spack ref to use'
+        required: true
+        type: string
+      run-self-hosted:
+        description: 'Use self-hosted runners for the test'
+        required: true
+        default: true
+        type: boolean
+jobs:
+  setup-ci:
+    name: Setup CI
+    runs-on: ubuntu-latest
+    env:
+      # Note, this needs to be updated in line with refs in the CI job below
+      BUILD_CI_WORKFLOW_VERSION: v3
+      # Which repository we get the manifest-to-test from
+      SPACK_MANIFEST_REPOSITORY: ACCESS-NRI/access-spack-packages
+    outputs:
+      spack-manifest-repository: ${{ env.SPACK_MANIFEST_REPOSITORY }}
+      # Matrices used in CI job
+      manifest-matrix: ${{ steps.set-manifest-matrix.outputs.matrix }}
+      config-matrix: ${{ steps.set-config-matrix-pr.outputs.all_changed_files || steps.set-config-matrix-dispatch.outputs.dirs }}
+      # Global defaults for CI job
+      spack-config-ref: ${{ inputs.spack-config-ref || github.event.pull_request.head.sha }}
+      spack-ref: ${{ inputs.spack-ref || steps.defaults.outputs.spack-ref }}
+    steps:
+      - name: Checkout spack-config
+        uses: actions/checkout@v6
+
+      - name: PR - Get dirs changed
+        id: set-config-matrix-pr
+        if: github.event_name == 'pull_request'
+        uses: tj-actions/changed-files@9426d40962ed5378910ee2e21d5f8c6fcbf2dd96  # v47.0.6
+        with:
+          dir_names: true  # we want a list of spack configuration directories (eg. v1.1, v1.2)
+          dir_names_max_depth: 1  # and don't care about subdirectories
+          dir_names_exclude_current_dir: true  # or files changed in the root directory
+          matrix: true  # and format it in a way understandable to GitHub actions matrices
+          # Below is an equivalent condition to on.pull_request.paths
+          files: |
+            v*/**
+            !v0.*/**
+
+      - name: Dispatch - Get config directory to test
+        id: set-config-matrix-dispatch
+        if: github.event_name == 'workflow_dispatch'
+        run: |
+          echo "dirs=${{ inputs.spack-config-directories-to-test }}" >> $GITHUB_OUTPUT
+
+      - name: Get ${{ env.SPACK_MANIFEST_REPOSITORY }}
+        uses: actions/checkout@v6
+        with:
+          repository: ${{ env.SPACK_MANIFEST_REPOSITORY }}
+
+      # This access-spack-packages matrix creation logic was adapted from
+      # https://github.com/ACCESS-NRI/access-spack-packages/blob/51064dc720f49c49e9680c368201e26081d4fa3f/.github/workflows/ci.yml#L58-L145
+      # Since these manifests use the jinja template variable 'package', we need it here too.
+      # Future manifest repositories may not need to associate the spec with a jinja variable, in which case this can be removed.
+      - name: Get Manifests from ${{ env.SPACK_MANIFEST_REPOSITORY }}
+        id: access-spack-packages
+        env:
+          ACCESS_SPACK_PACKAGES_ROOT_DIR: spack_repo/access/nri/packages
+        run: |
+          pkgs=$(find ${{ env.ACCESS_SPACK_PACKAGES_ROOT_DIR }}/ -mindepth 1 -maxdepth 1 -type d -printf '%P ')
+
+          echo "Packages found in access-spack-packages: $pkgs"
+
+          echo "pkgs=$pkgs" >> $GITHUB_OUTPUT
+
+      - name: Setup Manifest Matrix
+        id: set-manifest-matrix
+        # Get all packages that will be tested, then
+        # Get file paths to manifests for each package, and a template, then finally
+        # Convert into a JSON array for the matrix, one of the form:
+        # [
+        #   {"template_value": "mom5", "filepath": ".github/build-ci/manifests/mom5/intel.spack.yaml.j2"},
+        #   {"template_value": "mom5", "filepath": ".github/build-ci/manifests/mom5/gcc.spack.yaml.j2"},
+        #   {"template_value": "cice5", "filepath": ".github/build-ci/manifests/cice5/spack.yaml.j2"},
+        #   ...
+        # ]
+        run: |
+          pkgs="${{ steps.access-spack-packages.outputs.pkgs }}"
+
+          for pkg in $pkgs; do
+            # We want each manifest to have an associated injection of {{ package }} to $pkg
+            # Replace underscores with hyphens for the template value, as spack converts directory underscores to package name hyphens
+            template_value="${pkg//_/-}"
+
+            if [ -d ".github/build-ci/manifests/$pkg" ]; then  # Look for specific manifests for the package
+              # We space-separate the paths as we later use them in a for loop
+              manifest_paths=$(find .github/build-ci/manifests/$pkg -iname '*.j2' -type f -printf '%p ')
+            fi
+
+            if [[ -z "$manifest_paths" ]]; then  # Use the default templates if no specific manifests exist for the package
+              # Similarly, space-separate the paths for a later for loop. Default manifests are always directly under .github/build-ci/manifests
+              manifest_paths=$(find .github/build-ci/manifests/ -maxdepth 1 -type f -iname '*.j2' -printf '%p ')
+            fi
+
+            for manifest_path in $manifest_paths; do
+              json_entry=$(printf '{"template_value": "%s", "filepath": "%s"}' "$template_value" "$manifest_path")
+              json_entries+="${json_entry},"
+            done
+            unset manifest_paths
+          done
+
+          echo "$json_entries"
+
+          # Remove the trailing comma and wrap in square brackets
+          echo "matrix=[${json_entries%,}]" >> $GITHUB_OUTPUT
+
+      # End of adapted package generation logic...
+
+      - name: Checkout build-ci
+        uses: actions/checkout@v6
+        with:
+          repository: access-nri/build-ci
+          ref: ${{ env.BUILD_CI_WORKFLOW_VERSION }}
+
+      - name: Get default refs from build-ci workflow
+        id: defaults
+        # GitHub does not treat empty-string inputs as eligible for substitution with a default
+        # Since we are supporting both workflow_dispatch and pull_request triggers, the entrypoint inputs need to be filled in
+        # So we are getting the default values from the workflow file itself, and passing them back into the workflow
+        run: |
+          default_spack_ref=$(yq '.on.workflow_call.inputs."spack-ref".default' .github/workflows/ci.yml)
+
+          echo "Default refs from ${{ env.BUILD_CI_WORKFLOW_VERSION }}: spack-ref=$default_spack_ref"
+
+          echo "spack-ref=$default_spack_ref" >> $GITHUB_OUTPUT
+
+  ci:
+    name: CI
+    needs:
+      - setup-ci
+    strategy:
+      fail-fast: false
+      max-parallel: 5
+      matrix:
+        manifest: ${{ fromJson(needs.setup-ci.outputs.manifest-matrix) }}
+        config: ${{ fromJson(needs.setup-ci.outputs.config-matrix) }}
+        # Respectively of the form:
+        #   [
+        #     {"template_value": "mom5", "filepath": ".github/build-ci/manifests/mom5/intel.spack.yaml.j2"},
+        #     {"template_value": "mom5", "filepath": ".github/build-ci/manifests/mom5/gcc.spack.yaml.j2"},
+        #     ...
+        #   ]
+        # And:
+        #   [v1.1, v1.3, ...]
+    uses: access-nri/build-ci/.github/workflows/ci.yml@v3
+    with:
+      spack-manifest-repository: ${{ needs.setup-ci.outputs.spack-manifest-repository }}
+      spack-manifest-path: ${{ matrix.manifest.filepath }}
+      spack-manifest-data-path: .github/build-ci/data/standard_definitions.json
+      spack-manifest-data-pairs: |-
+        package ${{ matrix.manifest.template_value }}
+      spack-config-ref: ${{ needs.setup-ci.outputs.spack-config-ref }}
+      spack-ref: ${{ needs.setup-ci.outputs.spack-ref }}
+      container-image-version: :rocky-${{ matrix.config }}
+      # Workflow dispatch can switch depending on cluster/GitHub resourcing, otherwise run self-hosted
+      run-self-hosted: ${{ inputs.run-self-hosted || true }}
+    secrets:
+      spack-install-command-pat: ${{ secrets.SPACK_INSTALL_COMMAND_PAT }}
diff --git a/v1.1/ci/downstream/config.yaml b/v1.1/ci/downstream/config.yaml
index 896165f..de08a6d 100644
--- a/v1.1/ci/downstream/config.yaml
+++ b/v1.1/ci/downstream/config.yaml
@@ -1,3 +1,4 @@
+# Testing!
 config:
   install_tree:
     # Completely ignoring lower-precedence configuration options is supported with the :: notation for keys
diff --git a/v1.1/toolchains.yaml b/v1.1/toolchains.yaml
index 14425d2..68f725b 100644
--- a/v1.1/toolchains.yaml
+++ b/v1.1/toolchains.yaml
@@ -1,3 +1,4 @@
+# Testing out a change...
 toolchains:
   access_gcc:
   - spec: '%c=gcc'