diff --git a/toolchain/install/install_paths.cpp b/toolchain/install/install_paths.cpp
index e867af01e81e..59c4de4f6dc1 100644
--- a/toolchain/install/install_paths.cpp
+++ b/toolchain/install/install_paths.cpp
@@ -16,7 +16,7 @@ namespace Carbon {
 
 // The location within our Bazel output tree of the prefix_root.
 static constexpr llvm::StringLiteral PrefixRoot =
-    "_main/toolchain/install/prefix_root/";
+    "carbon/toolchain/install/prefix_root/";
 
 // Path within an install prefix for our marker of a valid install.
 static constexpr llvm::StringLiteral MarkerPath =
diff --git a/toolchain/install/install_paths_test.cpp b/toolchain/install/install_paths_test.cpp
index a436879ba513..85784f0e810e 100644
--- a/toolchain/install/install_paths_test.cpp
+++ b/toolchain/install/install_paths_test.cpp
@@ -81,7 +81,7 @@ class InstallPathsTest : public ::testing::Test {
 
 TEST_F(InstallPathsTest, PrefixRootDriver) {
   std::string installed_driver_path = test_runfiles_->Rlocation(
-      "_main/toolchain/install/prefix_root/bin/carbon");
+      "carbon/toolchain/install/prefix_root/bin/carbon");
 
   auto paths = InstallPaths::MakeExeRelative(installed_driver_path);
   ASSERT_THAT(paths.error(), Eq(std::nullopt)) << *paths.error();
@@ -90,7 +90,7 @@ TEST_F(InstallPathsTest, PrefixRootDriver) {
 
 TEST_F(InstallPathsTest, PrefixRootExplicit) {
   std::string marker_path = test_runfiles_->Rlocation(
-      "_main/toolchain/install/prefix_root/lib/carbon/carbon_install.txt");
+      "carbon/toolchain/install/prefix_root/lib/carbon/carbon_install.txt");
 
   llvm::StringRef prefix_path = marker_path;
   CARBON_CHECK(prefix_path.consume_back("lib/carbon/carbon_install.txt"))
@@ -109,7 +109,7 @@ TEST_F(InstallPathsTest, TestRunfiles) {
 
 TEST_F(InstallPathsTest, BinaryRunfiles) {
   std::string test_binary_path =
-      test_runfiles_->Rlocation("_main/toolchain/install/test_binary");
+      test_runfiles_->Rlocation("carbon/toolchain/install/test_binary");
   CARBON_CHECK(llvm::sys::fs::can_execute(test_binary_path))
       << test_binary_path;