diff --git a/third_party/icu/source/common/umapfile.cpp b/third_party/icu/source/common/umapfile.cpp
index cb8256d6d90ba..bb1d68de53c1d 100644
--- a/third_party/icu/source/common/umapfile.cpp
+++ b/third_party/icu/source/common/umapfile.cpp
@@ -26,10 +26,6 @@
 #include "udatamem.h"
 #include "umapfile.h"
 
-#if MAP_IMPLEMENTATION==MAP_STARBOARD
-#include "starboard/extension/memory_mapped_file.h"
-#endif
-
 /* memory-mapping base definitions ------------------------------------------ */
 
 #if MAP_IMPLEMENTATION==MAP_WIN32
@@ -99,14 +95,6 @@ typedef HANDLE MemoryMap;
     typedef void *MemoryMap;
 
 #   define IS_MAP(map) ((map)!=nullptr)
-#elif MAP_IMPLEMENTATION==MAP_STARBOARD
-#   include "starboard/file.h"
-#   include "cmemory.h"
-#   include <sys/mman.h>
-
-    typedef void *MemoryMap;
-
-#   define IS_MAP(map) ((map)!=NULL)
 #endif
 
 /*----------------------------------------------------------------------------*
@@ -352,93 +340,6 @@ typedef HANDLE MemoryMap;
         }
     }
 
-#elif MAP_IMPLEMENTATION==MAP_STARBOARD
-    U_CFUNC UBool
-    uprv_mapFile(UDataMemory *pData, const char *path, UErrorCode *status) {
-        if (U_FAILURE(*status)) {
-            return FALSE;
-        }
-
-        UDataMemory_init(pData); /* Clear the output struct.        */
-
-        /* open the input file */
-        SbFile file = SbFileOpen(path, kSbFileOpenOnly | kSbFileRead, NULL, NULL);
-        if (!SbFileIsValid(file)) {
-            return FALSE;
-        }
-
-        /* get the file length */
-        SbFileInfo info;
-        if (!SbFileGetInfo(file, &info)) {
-            SbFileClose(file);
-            return FALSE;
-        }
-
-        int32_t fileLength = info.size;
-        if (fileLength <= 20) {
-            SbFileClose(file);
-            return FALSE;
-        }
-
-        pData->heapAllocated = false;
-
-        const auto* memory_mapped_file_extension =
-            reinterpret_cast<const CobaltExtensionMemoryMappedFileApi*>(
-                SbSystemGetExtension(kCobaltExtensionMemoryMappedFileName));
-
-        if(memory_mapped_file_extension &&
-           strcmp(memory_mapped_file_extension->name,
-                  kCobaltExtensionMemoryMappedFileName) == 0 &&
-           memory_mapped_file_extension->version >= 1) {
-                void *p = memory_mapped_file_extension->MemoryMapFile(
-                        NULL, path, kSbMemoryMapProtectRead, 0,fileLength);
-                if(p) {
-                    pData->map=p;
-                    pData->pHeader=(const DataHeader *)p;
-                    pData->mapAddr=p;
-                    SbFileClose(file);
-                    return TRUE;
-                }
-            // If mmap extension didn't work, fall back to allocating
-        }
-
-        /* allocate the memory to hold the file data */
-        void *p = uprv_malloc(fileLength);
-        if (!p) {
-            SbFileClose(file);
-            return FALSE;
-        }
-
-        /* read the file */
-        if (fileLength != SbFileReadAll(file, static_cast<char *>(p), fileLength)) {
-            uprv_free(p);
-            SbFileClose(file);
-            return FALSE;
-        }
-
-        SbFileClose(file);
-        pData->map=p;
-        pData->pHeader=(const DataHeader *)p;
-        pData->mapAddr=p;
-        pData->heapAllocated = true;
-        return TRUE;
-    }
-
-    U_CFUNC void
-    uprv_unmapFile(UDataMemory *pData) {
-        if(pData!=NULL && pData->map!=NULL) {
-            if(pData->heapAllocated) {
-                uprv_free(pData->map);
-            } else {
-                size_t dataLen = (char *)pData->map - (char *)pData->mapAddr;
-                munmap(pData->mapAddr, dataLen);
-            }
-            pData->map     = NULL;
-            pData->mapAddr = NULL;
-            pData->pHeader = NULL;
-        }
-    }
-
 #elif MAP_IMPLEMENTATION==MAP_390DLL
     /*  390 specific Library Loading.
      *  This is the only platform left that dynamically loads an ICU Data Library.
diff --git a/third_party/icu/source/common/umapfile.h b/third_party/icu/source/common/umapfile.h
index c7cf2af8cf2bc..779ca0f1ff203 100644
--- a/third_party/icu/source/common/umapfile.h
+++ b/third_party/icu/source/common/umapfile.h
@@ -38,12 +38,16 @@ U_CFUNC void  uprv_unmapFile(UDataMemory *pData);
 #define MAP_POSIX       2
 #define MAP_STDIO       3
 #define MAP_390DLL      4
-#define MAP_STARBOARD   5
 
 #if UCONFIG_NO_FILE_IO
 #   define MAP_IMPLEMENTATION MAP_NONE
 #elif (U_PLATFORM == U_STARBOARD)
-#   define MAP_IMPLEMENTATION MAP_STARBOARD
+    /*
+     * Starboard of course can provide file access, and real memory mapping on
+     * some platforms, but it's not needed here since ICU data is linked into
+     * the binary.
+     */
+#   define MAP_IMPLEMENTATION MAP_NONE
 #elif U_PLATFORM_USES_ONLY_WIN32_API
 #   define MAP_IMPLEMENTATION MAP_WIN32
 #elif U_HAVE_MMAP || U_PLATFORM == U_PF_OS390