diff --git a/tests/integration/cuda/ci-test-integration.sh b/tests/integration/cuda/ci-test-integration.sh
index f3bfe2bc9..37c6f138f 100755
--- a/tests/integration/cuda/ci-test-integration.sh
+++ b/tests/integration/cuda/ci-test-integration.sh
@@ -4,19 +4,50 @@ set -e
 
 echo "Run Integration Test ${PROTEUS_CI_INTEGRATION_TEST}"
 
-# Use pre-installed LLVM 20 on matrix.
-export LLVM_INSTALL_DIR=/usr/lib64/llvm20
-echo "LLVM_INSTALL_DIR ${LLVM_INSTALL_DIR}"
+# LLVM/Clang version installed from conda-forge (replaces the previously assumed
+# system install at /usr/lib64/llvm20).
+PROTEUS_CI_LLVM_VERSION=20.1.8
+PYTHON_VERSION=3.12
 
 # Load cuda module.
 ml load cuda/12
 
+install_miniforge() {
+  local miniforge_dir="${1}"
+
+  mkdir -p "${miniforge_dir}"
+  wget -q --tries=5 --retry-connrefused --wait=5 \
+    "https://github.com/conda-forge/miniforge/releases/latest/download/Miniforge3-Linux-$(uname -m).sh" \
+    -O "${miniforge_dir}/miniforge.sh"
+  bash "${miniforge_dir}/miniforge.sh" -b -u -p "${miniforge_dir}"
+  rm "${miniforge_dir}/miniforge.sh"
+  source "${miniforge_dir}/etc/profile.d/conda.sh"
+}
+
 export TEST_DIR=${CI_PROJECT_DIR}/tests/integration/cuda/${PROTEUS_CI_INTEGRATION_TEST}
 
 mkdir -p /tmp/proteus-ci-$(basename ${TEST_DIR})-${CI_JOB_ID}
 pushd /tmp/proteus-ci-$(basename ${TEST_DIR})-${CI_JOB_ID}
 
-rm -rf build-proteus install-proteus build install
+rm -rf build-proteus install-proteus build install miniforge3
+
+# Install Clang/LLVM through conda.
+install_miniforge miniforge3
+# Use an older version of gcc to avoid issues with detecting Clang as the CUDA
+# compiler.
+conda create -y -q -n proteus --override-channels -c conda-forge \
+    python=${PYTHON_VERSION} clang=${PROTEUS_CI_LLVM_VERSION} clangxx=${PROTEUS_CI_LLVM_VERSION} \
+    pip pybind11 clangdev=${PROTEUS_CI_LLVM_VERSION} llvmdev=${PROTEUS_CI_LLVM_VERSION} \
+    lit=${PROTEUS_CI_LLVM_VERSION} mlir=${PROTEUS_CI_LLVM_VERSION} gcc=12 gxx=12
+conda activate proteus
+
+export LLVM_INSTALL_DIR=$(llvm-config --prefix)
+echo "LLVM_INSTALL_DIR ${LLVM_INSTALL_DIR}"
+
+# Make the conda LLVM discoverable by the test sub-project's find_package(proteus)
+# call. CMake reads CMAKE_PREFIX_PATH from the environment.
+export CMAKE_PREFIX_PATH="${CONDA_PREFIX}:${CONDA_PREFIX}/lib/cmake"
+
 bash ${TEST_DIR}/ci-build-and-run.sh
 
 popd
diff --git a/tests/integration/cuda/make-shared_proteus/Makefile b/tests/integration/cuda/make-shared_proteus/Makefile
index e6be8f652..8a8a790eb 100644
--- a/tests/integration/cuda/make-shared_proteus/Makefile
+++ b/tests/integration/cuda/make-shared_proteus/Makefile
@@ -9,6 +9,7 @@ all:
 		-Wl,-rpath,${PROTEUS_INSTALL_DIR}/lib64 \
 		-l:libproteus.so \
 		-l:libproteus_cudart_builtins.a \
+		-L${CUDA_HOME}/lib64/stubs \
 		-L${CUDA_HOME}/lib64 \
 		-lcuda \
 		-lcudart
diff --git a/tests/integration/cuda/make-static_proteus/Makefile b/tests/integration/cuda/make-static_proteus/Makefile
index c98920aef..f89cc060a 100644
--- a/tests/integration/cuda/make-static_proteus/Makefile
+++ b/tests/integration/cuda/make-static_proteus/Makefile
@@ -10,6 +10,7 @@ all:
 		-l:libproteus.a \
 		-l:libproteus_cudart_builtins.a \
 		${LLVM_LIBFLAGS} \
+		-L${CUDA_HOME}/lib64/stubs \
 		-L${CUDA_HOME}/lib64 \
 		-lcuda \
 		-lcudart \
diff --git a/tests/integration/cuda/make-static_proteus/ci-build-and-run.sh b/tests/integration/cuda/make-static_proteus/ci-build-and-run.sh
index 4fdb44343..eee884cea 100644
--- a/tests/integration/cuda/make-static_proteus/ci-build-and-run.sh
+++ b/tests/integration/cuda/make-static_proteus/ci-build-and-run.sh
@@ -19,7 +19,7 @@ LLVM_LIBS+=" "$(${LLVM_INSTALL_DIR}/bin/llvm-config --system-libs)
 
 cp -r ${TEST_DIR}/* .
 export PROTEUS_INSTALL_DIR=${PWD}/install-proteus
-export LLVM_LIBFLAGS="-L ${LLVM_LIBDIR} ${LLVM_LIBS} -llldCommon -llldELF"
+export LLVM_LIBFLAGS="-L ${LLVM_LIBDIR} ${LLVM_LIBS}"
 echo "LLVM_LIBFLAGS ${LLVM_LIBFLAGS}"
 make -j
 ./main
diff --git a/tests/integration/cuda/mpi-shared-cache/ci-build-and-run.sh b/tests/integration/cuda/mpi-shared-cache/ci-build-and-run.sh
index 6c206f03a..e89509051 100755
--- a/tests/integration/cuda/mpi-shared-cache/ci-build-and-run.sh
+++ b/tests/integration/cuda/mpi-shared-cache/ci-build-and-run.sh
@@ -23,7 +23,32 @@ run_mpi() {
     fi
 }
 
-# Build proteus with MPI enabled.
+# Build proteus with MPI enabled. Conda's linker does not follow the default
+# Matrix MVAPICH transitive library search paths during CMake's MPI link probe,
+# so make those paths explicit without changing the MPI selected by the module.
+MPI_RPATH_LINK_DIRS=()
+if [[ -n "${CONDA_PREFIX}" ]]; then
+    MPI_RPATH_LINK_DIRS+=(
+        "${CONDA_PREFIX}/lib"
+        "${CONDA_PREFIX}/x86_64-conda-linux-gnu/lib"
+    )
+fi
+MPI_RPATH_LINK_DIRS+=(
+    /lib64
+    /usr/tce/backend/installations/linux-rhel8-x86_64/gcc-10.3.1/intel-oneapi-compilers-2022.1.0-43xp3r52jx2q2rkf3ctzvskqu572xbky/compiler/2022.1.0/linux/compiler/lib/intel64_lin
+    /usr/tce/backend/installations/linux-rhel8-x86_64/intel-2021.6.0/mvapich2-2.3.7-2575ifqlr5fbj34wdlj2fo2tmqdrehia/lib
+    /usr/tce/backend/installations/linux-rhel8-x86_64/gcc-8.5.0/zlib-1.2.13-pwvjwcyuqiscffdc2x2lr7ti355xwohq/lib
+)
+MPI_RPATH_LINK_FLAGS=""
+for dir in "${MPI_RPATH_LINK_DIRS[@]}"; do
+    if [[ -d "${dir}" ]]; then
+        MPI_RPATH_LINK_FLAGS+="${MPI_RPATH_LINK_FLAGS:+ }-Wl,-rpath-link,${dir}"
+    fi
+done
+MPI_CMAKE_ARGS=(
+    -DCMAKE_EXE_LINKER_FLAGS="${MPI_RPATH_LINK_FLAGS}"
+)
+
 cmake -S ${CI_PROJECT_DIR} -B build-proteus \
     -DLLVM_INSTALL_DIR="${LLVM_INSTALL_DIR}" \
     -DCMAKE_C_COMPILER="${LLVM_INSTALL_DIR}/bin/clang" \
@@ -32,7 +57,8 @@ cmake -S ${CI_PROJECT_DIR} -B build-proteus \
     -DPROTEUS_ENABLE_CUDA=on \
     -DPROTEUS_ENABLE_MPI=on \
     -DENABLE_TESTS=off \
-    -DBUILD_SHARED=off
+    -DBUILD_SHARED=off \
+    "${MPI_CMAKE_ARGS[@]}"
 
 pushd build-proteus
 make -j install
@@ -44,7 +70,8 @@ cmake -S ${TEST_DIR} -B build \
     -DCMAKE_CXX_COMPILER="${LLVM_INSTALL_DIR}/bin/clang++" \
     -DCMAKE_CUDA_COMPILER="${LLVM_INSTALL_DIR}/bin/clang++" \
     -DCMAKE_CUDA_ARCHITECTURES=90 \
-    -Dproteus_DIR="${PWD}/install-proteus"
+    -Dproteus_DIR="${PWD}/install-proteus" \
+    "${MPI_CMAKE_ARGS[@]}"
 pushd build
 make -j
 popd