diff --git a/.Rbuildignore b/.Rbuildignore
index b058caf..da5d50b 100644
--- a/.Rbuildignore
+++ b/.Rbuildignore
@@ -8,3 +8,4 @@
 ^pkgdown$
 ^\.github$
 ^LICENSE\.md$
+^codecov\.yml$
diff --git a/.github/workflows/test-coverage.yaml b/.github/workflows/test-coverage.yaml
new file mode 100644
index 0000000..fefc52e
--- /dev/null
+++ b/.github/workflows/test-coverage.yaml
@@ -0,0 +1,61 @@
+# Workflow derived from https://github.com/r-lib/actions/tree/v2/examples
+# Need help debugging build failures? Start at https://github.com/r-lib/actions#where-to-find-help
+on:
+  push:
+    branches: [main, master]
+  pull_request:
+    branches: [main, master]
+
+name: test-coverage
+
+permissions: read-all
+
+jobs:
+  test-coverage:
+    runs-on: ubuntu-latest
+    env:
+      GITHUB_PAT: ${{ secrets.GITHUB_TOKEN }}
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: r-lib/actions/setup-r@v2
+        with:
+          use-public-rspm: true
+
+      - uses: r-lib/actions/setup-r-dependencies@v2
+        with:
+          extra-packages: any::covr, any::xml2
+          needs: coverage
+
+      - name: Test coverage
+        run: |
+          cov <- covr::package_coverage(
+            quiet = FALSE,
+            clean = FALSE,
+            install_path = file.path(normalizePath(Sys.getenv("RUNNER_TEMP"), winslash = "/"), "package")
+          )
+          covr::to_cobertura(cov)
+        shell: Rscript {0}
+
+      - uses: codecov/codecov-action@v4
+        with:
+          fail_ci_if_error: ${{ github.event_name != 'pull_request' && true || false }}
+          file: ./cobertura.xml
+          plugin: noop
+          disable_search: true
+          token: ${{ secrets.CODECOV_TOKEN }}
+
+      - name: Show testthat output
+        if: always()
+        run: |
+          ## --------------------------------------------------------------------
+          find '${{ runner.temp }}/package' -name 'testthat.Rout*' -exec cat '{}' \; || true
+        shell: bash
+
+      - name: Upload test results
+        if: failure()
+        uses: actions/upload-artifact@v4
+        with:
+          name: coverage-test-failures
+          path: ${{ runner.temp }}/package
diff --git a/README.Rmd b/README.Rmd
index 2e6417b..eb61c3b 100644
--- a/README.Rmd
+++ b/README.Rmd
@@ -15,6 +15,7 @@ knitr::opts_chunk$set(
 <!-- badges: start -->
 [![Project Status: WIP – Initial development is in progress, but there has not yet been a stable, usable release suitable for the public.](https://www.repostatus.org/badges/latest/wip.svg)](https://www.repostatus.org/#wip)
 [![R-CMD-check](https://github.com/WarwickCIM/ukgeographies/actions/workflows/R-CMD-check.yaml/badge.svg)](https://github.com/WarwickCIM/ukgeographies/actions/workflows/R-CMD-check.yaml)
+[![Codecov test coverage](https://codecov.io/gh/WarwickCIM/ukgeographies/branch/main/graph/badge.svg)](https://app.codecov.io/gh/WarwickCIM/ukgeographies?branch=main)
 <!-- badges: end -->
 
 > [!WARNING]  
diff --git a/README.md b/README.md
index 36a77d5..0dde1cf 100644
--- a/README.md
+++ b/README.md
@@ -10,6 +10,8 @@
 has not yet been a stable, usable release suitable for the
 public.](https://www.repostatus.org/badges/latest/wip.svg)](https://www.repostatus.org/#wip)
 [![R-CMD-check](https://github.com/WarwickCIM/ukgeographies/actions/workflows/R-CMD-check.yaml/badge.svg)](https://github.com/WarwickCIM/ukgeographies/actions/workflows/R-CMD-check.yaml)
+[![Codecov test
+coverage](https://codecov.io/gh/WarwickCIM/ukgeographies/branch/main/graph/badge.svg)](https://app.codecov.io/gh/WarwickCIM/ukgeographies?branch=main)
 <!-- badges: end -->
 
 > \[!WARNING\]  
diff --git a/codecov.yml b/codecov.yml
new file mode 100644
index 0000000..04c5585
--- /dev/null
+++ b/codecov.yml
@@ -0,0 +1,14 @@
+comment: false
+
+coverage:
+  status:
+    project:
+      default:
+        target: auto
+        threshold: 1%
+        informational: true
+    patch:
+      default:
+        target: auto
+        threshold: 1%
+        informational: true