diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index fde2ce6e..806b19b6 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -1,4 +1,4 @@
-name: 'CI'
+name: test
 
 on:
   push:
@@ -17,9 +17,6 @@ concurrency:
   group: ${{ github.workflow }}-${{ github.ref }}
   cancel-in-progress: true
 
-env:
-  DATA_PATH: /tmp/data
-
 jobs:
   check:
     uses: OpenAstronomy/github-actions-workflows/.github/workflows/tox.yml@924441154cf3053034c6513d5e06c69d262fb9a6  # v1.13.0
diff --git a/.github/workflows/downstream.yml b/.github/workflows/downstream.yml
index f15f1ec1..66a7d1ae 100644
--- a/.github/workflows/downstream.yml
+++ b/.github/workflows/downstream.yml
@@ -1,4 +1,4 @@
-name: Downstream
+name: test downstream packages
 
 on:
   workflow_dispatch:
@@ -16,9 +16,6 @@ on:
     tags:
       - '*'
 
-env:
-  DATA_PATH: /tmp/data
-
 # Only cancel in-progress jobs or runs for the current workflow
 #   This cancels the already triggered workflows for a specific PR without canceling
 #   other instances of this workflow (other PRs, scheduled triggers, etc) when something
@@ -32,12 +29,12 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - id: data_path
-        run: echo "path=${{ env.DATA_PATH }}" >> $GITHUB_OUTPUT
+        run: echo "path=${{ runner.temp }}/data" >> $GITHUB_OUTPUT
     outputs:
       data_path: ${{ steps.data_path.outputs.path }}
 
   crds_contexts:
-    uses: ./.github/workflows/contexts.yml
+    uses: spacetelescope/crds/.github/workflows/contexts.yml@master
 
   jwst:
     uses: OpenAstronomy/github-actions-workflows/.github/workflows/tox.yml@924441154cf3053034c6513d5e06c69d262fb9a6  # v1.13.0
@@ -67,6 +64,29 @@ jobs:
       envs: |
         - linux: py311-test-romancal-cov-xdist
 
+  romanisim_data:
+    needs: [ environment ]
+    uses: spacetelescope/romanisim/.github/workflows/retrieve_cache.yml@main
+    with:
+      cache_path: ${{ needs.environment.outputs.data_path }}
+
+  romanisim:
+    needs: [ romanisim_data ]
+    uses: OpenAstronomy/github-actions-workflows/.github/workflows/tox.yml@924441154cf3053034c6513d5e06c69d262fb9a6  # v1.13.0
+    with:
+      libraries: |
+        brew:
+          - eigen
+          - fftw
+      setenv: |
+        WEBBPSF_PATH: ${{ needs.romanisim_data.outputs.cache_path }}/webbpsf-data/
+        GALSIM_CAT_PATH: ${{ needs.romanisim_data.outputs.cache_path }}/galsim_data/real_galaxy_catalog_23.5_example.fits
+        FFTW_DIR: /opt/homebrew/opt/fftw/lib/
+      cache-path: ${{ needs.romanisim_data.outputs.cache_path }}
+      cache-key: ${{ needs.romanisim_data.outputs.cache_key }} 
+      envs: |
+        - linux: py311-test-romanisim-cov-xdist
+
   astropy:
     uses: OpenAstronomy/github-actions-workflows/.github/workflows/tox.yml@924441154cf3053034c6513d5e06c69d262fb9a6  # v1.13.0
     if: (github.repository == 'spacetelescope/gwcs' && (github.event_name == 'schedule' || github.event_name == 'push' || github.event_name == 'workflow_dispatch' || contains(github.event.pull_request.labels.*.name, 'Downstream CI')))
@@ -86,4 +106,4 @@ jobs:
       default_python: '3.11'
       envs: |
         - linux: ndcube
-        - linux: dkist
\ No newline at end of file
+        - linux: dkist
diff --git a/.github/workflows/romanisim_data.yml b/.github/workflows/romanisim_data.yml
new file mode 100644
index 00000000..aba64646
--- /dev/null
+++ b/.github/workflows/romanisim_data.yml
@@ -0,0 +1,18 @@
+name: download and cache romanisim data
+
+on:
+  schedule:
+    - cron: "42 4 * * 3"
+  workflow_dispatch:
+    inputs:
+      webbpsf_minimal:
+        description: minimal WebbPSF dataset
+        type: boolean
+        required: false
+        default: true
+
+jobs:
+  download_romanisim_data:
+    uses: spacetelescope/romanisim/.github/workflows/retrieve_cache.yml@main
+    with:
+      minimal: ${{ github.event_name != 'workflow_dispatch' && true || inputs.webbpsf_minimal }}
diff --git a/tox.ini b/tox.ini
index f5e2ae74..902b40f1 100644
--- a/tox.ini
+++ b/tox.ini
@@ -45,18 +45,24 @@ description =
     run tests
     jwst: of JWST pipeline
     romancal: of Romancal pipeline
+    romanisim: of Romanisim image simulation
     dev: with the latest developer version of key dependencies
     pyargs: with --pyargs on installed package
     warnings: treating warnings as errors
     cov: with coverage
     xdist: using parallel processing
-passenv =
+pass_env =
     HOME
     GITHUB_*
     TOXENV
     CI
     CODECOV_*
     DISPLAY
+    jwst,romancal: CRDS_*
+    romanisim,romancal: WEBBPSF_PATH
+    romanisim: GALSIM_CAT_PATH
+    romanisim: FFTW_DIR
+    romanisim: LIBRARY_PATH
 set_env =
     dev: PIP_EXTRA_INDEX_URL = https://pypi.anaconda.org/astropy/simple https://pypi.anaconda.org/liberfa/simple https://pypi.anaconda.org/scientific-python-nightly-wheels/simple
 
@@ -70,10 +76,9 @@ deps =
     cov: pytest-cov
     jwst: jwst[test] @ git+https://github.com/spacetelescope/jwst.git
     romancal: romancal[test] @ git+https://github.com/spacetelescope/romancal.git
+    romanisim: romanisim[test] @ git+https://github.com/spacetelescope/romanisim.git
     numpy123: numpy==1.23.*
     numpy125: numpy==1.25.*
-pass_env =
-    jwst,romancal: CRDS_*
 commands_pre =
     dev: pip install -r requirements-dev.txt -U --upgrade-strategy eager
     pip freeze
@@ -84,6 +89,7 @@ commands =
     pyargs: {toxinidir}/docs --pyargs gwcs \
     jwst: --pyargs jwst --ignore-glob=timeconversion --ignore-glob=associations --ignore-glob=scripts --show-capture=no \
     romancal: --pyargs romancal \
+    romanisim: --pyargs romanisim \
     cov: --cov=. --cov-config=pyproject.toml --cov-report=term-missing --cov-report=xml \
     {posargs}