diff --git a/packages/yarnpkg-fslib/sources/path.ts b/packages/yarnpkg-fslib/sources/path.ts
index ec2a3857ed1c..1c734404a6ee 100644
--- a/packages/yarnpkg-fslib/sources/path.ts
+++ b/packages/yarnpkg-fslib/sources/path.ts
@@ -88,6 +88,7 @@ export interface ConvertUtils {
 
 const WINDOWS_PATH_REGEXP = /^[a-zA-Z]:.*$/;
 const PORTABLE_PATH_REGEXP = /^\/[a-zA-Z]:.*$/;
+const UNC_PORTABLE_PATH_REGEXP = /^\/\/.*$/;
 
 // Path should look like "/N:/berry/scripts/plugin-pack.js"
 // And transform to "N:\berry\scripts\plugin-pack.js"
@@ -95,8 +96,14 @@ function fromPortablePath(p: Path): NativePath {
   if (process.platform !== 'win32')
     return p as NativePath;
 
-  return p.match(PORTABLE_PATH_REGEXP) ? p.substring(1).replace(/\//g, `\\`) : p;
-}
+  if (!(p.match(PORTABLE_PATH_REGEXP) || p.match(UNC_PORTABLE_PATH_REGEXP)))
+    return p as NativePath;
+
+  if (p.match(PORTABLE_PATH_REGEXP))
+    p = p.substring(1);
+
+  return p.replace(/\//g, `\\`);
+};
 
 // Path should look like "N:/berry/scripts/plugin-pack.js"
 // And transform to "/N:/berry/scripts/plugin-pack.js"
diff --git a/packages/yarnpkg-fslib/tests/npath.test.ts b/packages/yarnpkg-fslib/tests/npath.test.ts
index 22ce6374392a..96607bcdfc65 100644
--- a/packages/yarnpkg-fslib/tests/npath.test.ts
+++ b/packages/yarnpkg-fslib/tests/npath.test.ts
@@ -75,6 +75,36 @@ describe(`Portable paths`, () => {
             const outputPath = `/C:`;
             expect(npath.toPortablePath(inputPath)).toEqual(outputPath);
           });
+
+          it(`should support UNC Windows paths (//[server]/[sharename]/)`, () => {
+            const inputPath = '\\\\Server01\\user\\docs\\Letter.txt';
+            const outputPath = `//Server01/user/docs/Letter.txt`;
+            expect(npath.toPortablePath(inputPath)).toEqual(outputPath);
+          });
+
+          it(`should support Long UNC Windows paths (//?/[server]/[sharename]/)`, () => {
+            const inputPath = '\\\\?\\Server01\\user\\docs\\Letter.txt';
+            const outputPath = `//?/Server01/user/docs/Letter.txt`;
+            expect(npath.toPortablePath(inputPath)).toEqual(outputPath);
+          });
+
+          it(`should support Long UNC Windows paths (//?/UNC/[server]/[sharename]/)`, () => {
+            const inputPath = '\\\\?\\UNC\\Server01\\user\\docs\\Letter.txt';
+            const outputPath = `//?/UNC/Server01/user/docs/Letter.txt`;
+            expect(npath.toPortablePath(inputPath)).toEqual(outputPath);
+          });
+
+          it(`should support Long UNC Windows paths (//?/[drive_spec]:/)`, () => {
+            const inputPath = '\\\\?\\C:\\user\\docs\\Letter.txt';
+            const outputPath = `//?/C:/user/docs/Letter.txt`;
+            expect(npath.toPortablePath(inputPath)).toEqual(outputPath);
+          });
+
+          it(`should support Long UNC Windows paths with dot (//./[physical_device]/)`, () => {
+            const inputPath = '\\\\.\\PhysicalDevice\\user\\docs\\Letter.txt';
+            const outputPath = `//./PhysicalDevice/user/docs/Letter.txt`;
+            expect(npath.toPortablePath(inputPath)).toEqual(outputPath);
+          });
         }
       });
 
@@ -127,6 +157,36 @@ describe(`Portable paths`, () => {
             const outputPath = `C:`;
             expect(npath.fromPortablePath(inputPath)).toEqual(outputPath);
           });
+
+          it(`should transform back UNC Windows paths (//[server]/[sharename]/)`, () => {
+            const inputPath = `//Server01/user/docs/Letter.txt`;
+            const outputPath = '\\\\Server01\\user\\docs\\Letter.txt';
+            expect(npath.fromPortablePath(inputPath)).toEqual(outputPath);
+          });
+
+          it(`should transform back Long UNC Windows paths (//?/[server]/[sharename]/)`, () => {
+            const inputPath = `//?/Server01/user/docs/Letter.txt`;
+            const outputPath = '\\\\?\\Server01\\user\\docs\\Letter.txt';
+            expect(npath.fromPortablePath(inputPath)).toEqual(outputPath);
+          });
+
+          it(`should transform back Long UNC Windows paths (//?/UNC/[server]/[sharename]/)`, () => {
+            const inputPath = `//?/UNC/Server01/user/docs/Letter.txt`;
+            const outputPath = '\\\\?\\UNC\\Server01\\user\\docs\\Letter.txt';
+            expect(npath.fromPortablePath(inputPath)).toEqual(outputPath);
+          });
+
+          it(`should transform back Long UNC Windows paths (//?/[drive_spec]:/)`, () => {
+            const inputPath = `//?/C:/user/docs/Letter.txt`;
+            const outputPath = '\\\\?\\C:\\user\\docs\\Letter.txt';
+            expect(npath.fromPortablePath(inputPath)).toEqual(outputPath);
+          });
+
+          it(`should transform back Long UNC Windows paths with dot (//./[physical_device]/)`, () => {
+            const inputPath = `//./PhysicalDevice/user/docs/Letter.txt`;
+            const outputPath = '\\\\.\\PhysicalDevice\\user\\docs\\Letter.txt';
+            expect(npath.fromPortablePath(inputPath)).toEqual(outputPath);
+          });
         }
       });
     });