diff --git a/utils/build_swift/build_swift/defaults.py b/utils/build_swift/build_swift/defaults.py
index 07d0fbc228b6f..446f16208b5df 100644
--- a/utils/build_swift/build_swift/defaults.py
+++ b/utils/build_swift/build_swift/defaults.py
@@ -43,7 +43,7 @@
 
 # Options that can be "configured" by command line options
 
-BUILD_VARIANT = 'Debug'
+BUILD_VARIANT = 'RelWithDebInfo'
 CMAKE_GENERATOR = 'Ninja'
 
 COMPILER_VENDOR = 'none'
diff --git a/utils/build_swift/build_swift/driver_arguments.py b/utils/build_swift/build_swift/driver_arguments.py
index e0e9f7cd87356..cf0a31a45481b 100644
--- a/utils/build_swift/build_swift/driver_arguments.py
+++ b/utils/build_swift/build_swift/driver_arguments.py
@@ -71,7 +71,7 @@ def _apply_default_arguments(args):
 
     # Set the default build variant.
     if args.build_variant is None:
-        args.build_variant = 'Debug'
+        args.build_variant = 'RelWithDebInfo'
 
     if args.llvm_build_variant is None:
         args.llvm_build_variant = args.build_variant
@@ -950,7 +950,7 @@ def create_argument_parser():
 
     with mutually_exclusive_group():
 
-        set_defaults(build_variant='Debug')
+        set_defaults(build_variant='RelWithDebInfo')
 
         option(['-d', '--debug'], store('build_variant'),
                const='Debug',
diff --git a/utils/build_swift/tests/expected_options.py b/utils/build_swift/tests/expected_options.py
index 60db08eef2fc7..0c14d63430ab0 100644
--- a/utils/build_swift/tests/expected_options.py
+++ b/utils/build_swift/tests/expected_options.py
@@ -132,7 +132,7 @@
     'build_tvos': True,
     'build_tvos_device': False,
     'build_tvos_simulator': False,
-    'build_variant': 'Debug',
+    'build_variant': 'RelWithDebInfo',
     'build_watchos': True,
     'build_watchos_device': False,
     'build_watchos_simulator': False,
@@ -151,7 +151,7 @@
     'cmake': None,
     'cmake_generator': 'Ninja',
     'cmark_assertions': True,
-    'cmark_build_variant': 'Debug',
+    'cmark_build_variant': 'RelWithDebInfo',
     'color_in_tests': True,
     'compiler_vendor': defaults.COMPILER_VENDOR,
     'coverage_db': None,
@@ -214,8 +214,8 @@
     'extra_swift_cmake_options': [],
     'swift_debuginfo_non_lto_args': None,
     'force_optimized_typechecker': False,
-    'foundation_build_variant': 'Debug',
-    'foundation_tests_build_variant': 'Debug',
+    'foundation_build_variant': 'RelWithDebInfo',
+    'foundation_tests_build_variant': 'RelWithDebInfo',
     'host_cc': None,
     'host_cxx': None,
     'host_libtool': None,
@@ -233,20 +233,20 @@
     'ios': False,
     'ios_all': False,
     'legacy_impl': False,
-    'libdispatch_build_variant': 'Debug',
-    'libxml2_build_variant': 'Debug',
+    'libdispatch_build_variant': 'RelWithDebInfo',
+    'libxml2_build_variant': 'RelWithDebInfo',
     'linux_archs': None,
     'lit_jobs': multiprocessing.cpu_count(),
-    'zlib_build_variant': 'Debug',
-    'curl_build_variant': 'Debug',
+    'zlib_build_variant': 'RelWithDebInfo',
+    'curl_build_variant': 'RelWithDebInfo',
     'bootstrapping_mode': None,
     'lit_args': '-sv',
     'llbuild_assertions': True,
     'lldb_assertions': True,
-    'lldb_build_variant': 'Debug',
+    'lldb_build_variant': 'RelWithDebInfo',
     'lldb_build_with_xcode': '0',
     'llvm_assertions': True,
-    'llvm_build_variant': 'Debug',
+    'llvm_build_variant': 'RelWithDebInfo',
     'llvm_cmake_options': [],
     'llvm_enable_modules': False,
     'llvm_include_tests': True,
@@ -276,7 +276,7 @@
     'stress_test': False,
     'swift_analyze_code_coverage': defaults.SWIFT_ANALYZE_CODE_COVERAGE,
     'swift_assertions': True,
-    'swift_build_variant': 'Debug',
+    'swift_build_variant': 'RelWithDebInfo',
     'swift_compiler_version': None,
     'swift_disable_dead_stripping': False,
     'swift_darwin_module_archs': None,
@@ -286,7 +286,7 @@
     'swift_runtime_fixed_backtracer_path': None,
     'swift_stdlib_assertions': True,
     'swift_stdlib_strict_availability': False,
-    'swift_stdlib_build_variant': 'Debug',
+    'swift_stdlib_build_variant': 'RelWithDebInfo',
     'swift_tools_ld64_lto_codegen_only_for_supporting_targets': False,
     'swift_tools_max_parallel_lto_link_jobs':
         defaults.SWIFT_MAX_PARALLEL_LTO_LINK_JOBS,