diff --git a/changelog_unreleased/flow/10397.md b/changelog_unreleased/flow/10397.md
new file mode 100644
index 000000000..3df2ddcc3
--- /dev/null
+++ b/changelog_unreleased/flow/10397.md
@@ -0,0 +1,15 @@
+#### Support `this` type annotation in functions via `babel-flow` (#10397 by @sosukesuzuki)
+
+`this` type annotation is supported since [Babel 7.13](https://babeljs.io/blog/2021/02/22/7.13.0#new-flow-features-12193httpsgithubcombabelbabelpull12193-12234httpsgithubcombabelbabelpull12234).
+
+```js
+// Input
+var foo: (this: boolean) => void;
+
+// Prettier stable
+SyntaxError: Unexpected token, expected ")" (1:15)
+
+// Prettier main
+var foo: (this: boolean) => void;
+
+```
diff --git a/package.json b/package.json
index aba976076..7fcdf433a 100644
--- a/package.json
+++ b/package.json
@@ -22,7 +22,7 @@
   "dependencies": {
     "@angular/compiler": "11.2.1",
     "@babel/code-frame": "7.12.13",
-    "@babel/parser": "7.12.17",
+    "@babel/parser": "7.13.4",
     "@glimmer/syntax": "0.77.1",
     "@iarna/toml": "2.2.5",
     "@typescript-eslint/typescript-estree": "4.15.1",
diff --git a/tests/flow/this-annotation/__snapshots__/jsfmt.spec.js.snap b/tests/flow/this-annotation/__snapshots__/jsfmt.spec.js.snap
index 6c97fb86a..12da03297 100644
--- a/tests/flow/this-annotation/__snapshots__/jsfmt.spec.js.snap
+++ b/tests/flow/this-annotation/__snapshots__/jsfmt.spec.js.snap
@@ -54,17 +54,6 @@ function baz(this: number, ...a) {}
 ================================================================================
 `;
 
-exports[`function_type.js - {"trailingComma":"all"} [babel-flow] format 1`] = `
-"Unexpected token, expected \\")\\" (3:16)
-  1 | // @flow
-  2 |
-> 3 | type T = (this : number, a : string, b : number) => void
-    |                ^
-  4 |
-  5 | type U = (this : number, ...c : any) => void
-  6 |"
-`;
-
 exports[`function_type.js - {"trailingComma":"all"} format 1`] = `
 ====================================options=====================================
 parsers: ["flow", "babel-flow"]
@@ -92,17 +81,6 @@ type V = (this: number) => void;
 ================================================================================
 `;
 
-exports[`line_break.js - {"trailingComma":"all"} [babel-flow] format 1`] = `
-"Unexpected token, expected \\")\\" (3:15)
-  1 | // @flow
-  2 |
-> 3 | type T = (this: boolean,
-    |               ^
-  4 |           a: number,
-  5 |
-  6 |           b: number,"
-`;
-
 exports[`line_break.js - {"trailingComma":"all"} format 1`] = `
 ====================================options=====================================
 parsers: ["flow", "babel-flow"]
@@ -195,17 +173,6 @@ class A {
 ================================================================================
 `;
 
-exports[`union_type.js - {"trailingComma":"all"} [babel-flow] format 1`] = `
-"Unexpected token, expected \\")\\" (4:7)
-  2 |
-  3 | type A = (
-> 4 |   this: | SupperLongLongLongLongLongLongLongLongLongLongLongType | FooBarBazLorem12345,
-    |       ^
-  5 |   b: number,
-  6 | ) => boolean;
-  7 |"
-`;
-
 exports[`union_type.js - {"trailingComma":"all"} format 1`] = `
 ====================================options=====================================
 parsers: ["flow", "babel-flow"]
diff --git a/tests/flow/this-annotation/jsfmt.spec.js b/tests/flow/this-annotation/jsfmt.spec.js
index 4d93126a0..eaab82f9e 100644
--- a/tests/flow/this-annotation/jsfmt.spec.js
+++ b/tests/flow/this-annotation/jsfmt.spec.js
@@ -1,6 +1,3 @@
 run_spec(__dirname, ["flow", "babel-flow"], {
   trailingComma: "all",
-  errors: {
-    "babel-flow": ["function_type.js", "line_break.js", "union_type.js"],
-  },
 });
diff --git a/tests_config/run_spec.js b/tests_config/run_spec.js
index ea8baaed3..f97e8a702 100644
--- a/tests_config/run_spec.js
+++ b/tests_config/run_spec.js
@@ -47,6 +47,27 @@ const unstableTests = new Map(
   })
 );
 
+// This is temporary.
+// This will be removed once https://github.com/babel/babel/issues/12915 is fixed
+const unstableAstTests = new Map(
+  [
+    [
+      "flow/function-parentheses/single.js",
+      (options) =>
+        options.parser.startsWith("babel") && options.arrowParens !== "avoid",
+    ],
+    [
+      "flow/function-parentheses/test.js",
+      (options) => options.parser.startsWith("babel"),
+    ],
+  ].map((fixture) => {
+    const [file, isUnstable = () => true] = Array.isArray(fixture)
+      ? fixture
+      : [fixture];
+    return [path.join(__dirname, "../tests/", file), isUnstable];
+  })
+);
+
 const espreeDisabledTests = new Set(
   [
     // These tests only work for `babel`
@@ -65,6 +86,16 @@ const isUnstable = (filename, options) => {
   return testFunction(options);
 };
 
+const isAstUnstable = (filename, options) => {
+  const testFunction = unstableAstTests.get(filename);
+
+  if (!testFunction) {
+    return false;
+  }
+
+  return testFunction(options);
+};
+
 const shouldThrowOnFormat = (filename, options) => {
   const { errors = {} } = options;
   if (errors === true) {
@@ -293,13 +324,18 @@ function runTest({
     });
   }
 
+  const isAstUnstableTest = isAstUnstable(filename, formatOptions);
   // Some parsers skip parsing empty files
   if (formatResult.changed && code.trim()) {
     test(`[${parser}] compare AST`, () => {
       const { input, output } = formatResult;
       const originalAst = parse(input, formatOptions);
       const formattedAst = parse(output, formatOptions);
-      expect(formattedAst).toEqual(originalAst);
+      if (isAstUnstableTest) {
+        expect(formattedAst).not.toEqual(originalAst);
+      } else {
+        expect(formattedAst).toEqual(originalAst);
+      }
     });
   }
 
diff --git a/yarn.lock b/yarn.lock
index 2ecab2ab4..250b1c09f 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -267,15 +267,10 @@
     chalk "^2.0.0"
     js-tokens "^4.0.0"
 
-"@babel/parser@7.12.17":
-  version "7.12.17"
-  resolved "https://registry.yarnpkg.com/@babel/parser/-/parser-7.12.17.tgz#bc85d2d47db38094e5bb268fc761716e7d693848"
-  integrity sha512-r1yKkiUTYMQ8LiEI0UcQx5ETw5dpTLn9wijn9hk6KkTtOK95FndDN10M+8/s6k/Ymlbivw0Av9q4SlgF80PtHg==
-
-"@babel/parser@^7.1.0", "@babel/parser@^7.12.13", "@babel/parser@^7.12.17", "@babel/parser@^7.7.0":
-  version "7.12.17"
-  resolved "https://registry.yarnpkg.com/@babel/parser/-/parser-7.12.17.tgz#bc85d2d47db38094e5bb268fc761716e7d693848"
-  integrity sha512-r1yKkiUTYMQ8LiEI0UcQx5ETw5dpTLn9wijn9hk6KkTtOK95FndDN10M+8/s6k/Ymlbivw0Av9q4SlgF80PtHg==
+"@babel/parser@7.13.4", "@babel/parser@^7.1.0", "@babel/parser@^7.12.13", "@babel/parser@^7.12.17", "@babel/parser@^7.7.0":
+  version "7.13.4"
+  resolved "https://registry.yarnpkg.com/@babel/parser/-/parser-7.13.4.tgz#340211b0da94a351a6f10e63671fa727333d13ab"
+  integrity sha512-uvoOulWHhI+0+1f9L4BoozY7U5cIkZ9PgJqvb041d6vypgUmtVPG4vmGm4pSggjl8BELzvHyUeJSUyEMY6b+qA==
 
 "@babel/plugin-proposal-async-generator-functions@^7.12.13":
   version "7.12.13"
@@ -3078,7 +3073,6 @@ eslint-plugin-jest@24.1.5:
 
 "eslint-plugin-prettier-internal-rules@link:scripts/tools/eslint-plugin-prettier-internal-rules":
   version "0.0.0"
-  uid ""
 
 eslint-plugin-react@7.22.0:
   version "7.22.0"