diff --git a/.changeset/vite-plugin-preserve-authority-port.md b/.changeset/vite-plugin-preserve-authority-port.md
new file mode 100644
index 00000000000..82acf436173
--- /dev/null
+++ b/.changeset/vite-plugin-preserve-authority-port.md
@@ -0,0 +1,7 @@
+---
+"@cloudflare/vite-plugin": patch
+---
+
+Preserve HTTP/2 `:authority` header and non-default port in dev server requests
+
+When Vite runs over HTTPS with HTTP/2 enabled, browsers send authority via the `:authority` pseudo-header rather than `Host`. Previously, pseudo-headers were omitted when creating Fetch requests, causing non-default ports to be dropped from `request.url` and `X-Forwarded-Host`. Authority and scheme are now preserved from HTTP/2 pseudo-headers and request properties.
diff --git a/packages/vite-plugin-cloudflare/src/__tests__/utils.spec.ts b/packages/vite-plugin-cloudflare/src/__tests__/utils.spec.ts
index cfe6729887e..39e236cf84a 100644
--- a/packages/vite-plugin-cloudflare/src/__tests__/utils.spec.ts
+++ b/packages/vite-plugin-cloudflare/src/__tests__/utils.spec.ts
@@ -1,14 +1,20 @@
+import { EventEmitter } from "node:events";
 import http from "node:http";
 import net from "node:net";
 import * as path from "node:path";
 import { Response as MiniflareResponse } from "miniflare";
 import { afterEach, beforeEach, describe, test } from "vitest";
 import {
+	createRequestForIncomingMessage,
 	createRequestHandler,
+	getAuthority,
 	getForwardedProto,
 	getOutputDirectory,
+	getScheme,
+	toMiniflareRequest,
 } from "../utils";
 import type { AddressInfo } from "node:net";
+import type * as vite from "vite";
 
 describe("getOutputDirectory", () => {
 	test("returns the correct output if `environments[environmentName].build.outDir` is defined", ({
@@ -100,6 +106,211 @@ describe("getForwardedProto", () => {
 	});
 });
 
+describe("getAuthority", () => {
+	test("returns undefined when header and authority property are missing", ({
+		expect,
+	}) => {
+		expect(getAuthority({ headers: {} })).toBeUndefined();
+	});
+
+	test("extracts authority from `:authority` header", ({ expect }) => {
+		expect(getAuthority({ headers: { ":authority": "localhost:5173" } })).toBe(
+			"localhost:5173"
+		);
+	});
+
+	test("handles string array for `:authority` header", ({ expect }) => {
+		expect(
+			getAuthority({ headers: { ":authority": ["localhost:5173"] } })
+		).toBe("localhost:5173");
+	});
+
+	test("extracts authority from `authority` property on request", ({
+		expect,
+	}) => {
+		expect(getAuthority({ headers: {}, authority: "localhost:5173" })).toBe(
+			"localhost:5173"
+		);
+	});
+
+	test("prioritizes `:authority` header over `authority` property", ({
+		expect,
+	}) => {
+		expect(
+			getAuthority({
+				headers: { ":authority": "header-host:5173" },
+				authority: "prop-host:5173",
+			})
+		).toBe("header-host:5173");
+	});
+
+	test("returns undefined when `:authority` is an empty string", ({
+		expect,
+	}) => {
+		expect(getAuthority({ headers: { ":authority": "" } })).toBeUndefined();
+	});
+});
+
+describe("getScheme", () => {
+	test("returns undefined when header and scheme property are missing", ({
+		expect,
+	}) => {
+		expect(getScheme({ headers: {} })).toBeUndefined();
+	});
+
+	test("returns https: when `:scheme` header is `https`", ({ expect }) => {
+		expect(getScheme({ headers: { ":scheme": "https" } })).toBe("https:");
+	});
+
+	test("returns http: when `:scheme` header is `http`", ({ expect }) => {
+		expect(getScheme({ headers: { ":scheme": "http" } })).toBe("http:");
+	});
+
+	test("is case-insensitive", ({ expect }) => {
+		expect(getScheme({ headers: { ":scheme": "HTTPS" } })).toBe("https:");
+	});
+
+	test("handles string array for `:scheme` header", ({ expect }) => {
+		expect(getScheme({ headers: { ":scheme": ["https"] } })).toBe("https:");
+	});
+
+	test("extracts scheme from `scheme` property on request", ({ expect }) => {
+		expect(getScheme({ headers: {}, scheme: "https" })).toBe("https:");
+	});
+
+	test("returns undefined for unsupported schemes", ({ expect }) => {
+		expect(getScheme({ headers: { ":scheme": "ws" } })).toBeUndefined();
+		expect(getScheme({ headers: { ":scheme": "" } })).toBeUndefined();
+	});
+});
+
+describe("createRequestForIncomingMessage and toMiniflareRequest", () => {
+	test("preserves non-default port and hostname from `:authority` in request.url", ({
+		expect,
+	}) => {
+		const res = new EventEmitter() as unknown as http.ServerResponse;
+		const req = {
+			method: "GET",
+			url: "/path?query=1",
+			headers: {
+				":authority": "localhost:5173",
+				":scheme": "https",
+			},
+			rawHeaders: [":authority", "localhost:5173", ":scheme", "https"],
+			socket: {},
+		} as unknown as vite.Connect.IncomingMessage;
+
+		const request = createRequestForIncomingMessage(req, res);
+		expect(request.url).toBe("https://localhost:5173/path?query=1");
+		expect(request.headers.get("Host")).toBe("localhost:5173");
+	});
+
+	test("preserves non-default port with IPv6 authority", ({ expect }) => {
+		const res = new EventEmitter() as unknown as http.ServerResponse;
+		const req = {
+			method: "GET",
+			url: "/path",
+			headers: {
+				":authority": "[::1]:5173",
+				":scheme": "https",
+			},
+			rawHeaders: [":authority", "[::1]:5173", ":scheme", "https"],
+			socket: {},
+		} as unknown as vite.Connect.IncomingMessage;
+
+		const request = createRequestForIncomingMessage(req, res);
+		expect(request.url).toBe("https://[::1]:5173/path");
+		expect(request.headers.get("Host")).toBe("[::1]:5173");
+	});
+
+	test("toMiniflareRequest sets X-Forwarded-Host including port when missing", ({
+		expect,
+	}) => {
+		const res = new EventEmitter() as unknown as http.ServerResponse;
+		const req = {
+			method: "GET",
+			url: "/",
+			headers: {
+				":authority": "localhost:5173",
+				":scheme": "https",
+			},
+			rawHeaders: [":authority", "localhost:5173", ":scheme", "https"],
+			socket: {},
+		} as unknown as vite.Connect.IncomingMessage;
+
+		const request = createRequestForIncomingMessage(req, res);
+		const miniflareRequest = toMiniflareRequest(request);
+
+		expect(miniflareRequest.headers.get("X-Forwarded-Host")).toBe(
+			"localhost:5173"
+		);
+	});
+
+	test("toMiniflareRequest preserves existing X-Forwarded-Host if already set", ({
+		expect,
+	}) => {
+		const res = new EventEmitter() as unknown as http.ServerResponse;
+		const req = {
+			method: "GET",
+			url: "/",
+			headers: {
+				":authority": "localhost:5173",
+				":scheme": "https",
+				"x-forwarded-host": "external-proxy.com:8443",
+			},
+			rawHeaders: [
+				":authority",
+				"localhost:5173",
+				":scheme",
+				"https",
+				"x-forwarded-host",
+				"external-proxy.com:8443",
+			],
+			socket: {},
+		} as unknown as vite.Connect.IncomingMessage;
+
+		const request = createRequestForIncomingMessage(req, res);
+		const miniflareRequest = toMiniflareRequest(request);
+
+		expect(miniflareRequest.headers.get("X-Forwarded-Host")).toBe(
+			"external-proxy.com:8443"
+		);
+	});
+
+	test("prioritizes `:authority` over a stale or port-less `Host` header", ({
+		expect,
+	}) => {
+		const res = new EventEmitter() as unknown as http.ServerResponse;
+		const req = {
+			method: "GET",
+			url: "/path",
+			headers: {
+				":authority": "localhost:5173",
+				":scheme": "https",
+				host: "localhost",
+			},
+			rawHeaders: [
+				":authority",
+				"localhost:5173",
+				":scheme",
+				"https",
+				"host",
+				"localhost",
+			],
+			socket: {},
+		} as unknown as vite.Connect.IncomingMessage;
+
+		const request = createRequestForIncomingMessage(req, res);
+		expect(request.url).toBe("https://localhost:5173/path");
+		expect(request.headers.get("Host")).toBe("localhost:5173");
+
+		const miniflareRequest = toMiniflareRequest(request);
+		expect(miniflareRequest.headers.get("X-Forwarded-Host")).toBe(
+			"localhost:5173"
+		);
+	});
+});
+
 describe("createRequestHandler", () => {
 	// Use a real HTTP server so that `req`, `res`, and `req.socket` look like
 	// what `createRequest` from `@remix-run/node-fetch-server` expects in
diff --git a/packages/vite-plugin-cloudflare/src/utils.ts b/packages/vite-plugin-cloudflare/src/utils.ts
index f30ca3dc063..92c5c15f36f 100644
--- a/packages/vite-plugin-cloudflare/src/utils.ts
+++ b/packages/vite-plugin-cloudflare/src/utils.ts
@@ -130,7 +130,7 @@ export function satisfiesMinimumViteVersion(minVersion: string): boolean {
 	return semverGte(viteVersion, minVersion);
 }
 
-function createRequestForIncomingMessage(
+export function createRequestForIncomingMessage(
 	req: vite.Connect.IncomingMessage,
 	res: http.ServerResponse,
 	options?: { protocol?: "http:" | "https:"; host?: string }
@@ -144,8 +144,13 @@ function createRequestForIncomingMessage(
 	const headers = createHeaders(req);
 	const protocol =
 		options?.protocol ??
+		getScheme(req) ??
 		("encrypted" in req.socket && req.socket.encrypted ? "https:" : "http:");
-	const host = options?.host ?? headers.get("Host") ?? "localhost";
+	const host =
+		options?.host ?? getAuthority(req) ?? headers.get("Host") ?? "localhost";
+	if (headers.get("Host") !== host) {
+		headers.set("Host", host);
+	}
 	const url = new URL(req.url ?? "/", `${protocol}//${host}`);
 	const init: RequestInit & { duplex?: "half" } = {
 		method,
@@ -212,8 +217,8 @@ function createCancellableRequestBody(
 	});
 }
 
-function toMiniflareRequest(request: Request): MiniflareRequest {
-	const host = request.headers.get("Host");
+export function toMiniflareRequest(request: Request): MiniflareRequest {
+	const host = request.headers.get("Host") ?? new URL(request.url).host;
 	const xForwardedHost = request.headers.get("X-Forwarded-Host");
 
 	if (host && !xForwardedHost) {
@@ -264,3 +269,59 @@ export function getForwardedProto(req: {
 	}
 	return undefined;
 }
+
+/**
+ * Extracts the authority (host and port) from an incoming Node.js request.
+ *
+ * In HTTP/2, browsers pass the host and port in the `:authority` pseudo-header
+ * rather than the HTTP/1.1 `Host` header. This helper inspects `:authority`
+ * (or the `authority` property on `http2.Http2ServerRequest`) so that ports
+ * are preserved when converting Node requests to standard Fetch requests.
+ *
+ * @param req Incoming request containing HTTP headers and optional authority property
+ * @returns The authority string (e.g. "localhost:5173"), or undefined if not present
+ */
+export function getAuthority(req: {
+	headers: http.IncomingHttpHeaders;
+	authority?: string;
+}): string | undefined {
+	const raw = req.headers[":authority"];
+	const value = Array.isArray(raw) ? raw[0] : raw;
+	if (value) {
+		return value;
+	}
+	if (typeof req.authority === "string" && req.authority) {
+		return req.authority;
+	}
+	return undefined;
+}
+
+/**
+ * Extracts the scheme from an incoming Node.js request.
+ *
+ * Checks the `:scheme` pseudo-header in HTTP/2 requests or the `scheme`
+ * property on `http2.Http2ServerRequest`.
+ *
+ * @param req Incoming request containing HTTP headers and optional scheme property
+ * @returns The normalized scheme ("http:" or "https:"), or undefined if not present or unsupported
+ */
+export function getScheme(req: {
+	headers: http.IncomingHttpHeaders;
+	scheme?: string;
+}): "http:" | "https:" | undefined {
+	const raw = req.headers[":scheme"];
+	const value = Array.isArray(raw) ? raw[0] : raw;
+	if (value) {
+		const lower = value.toLowerCase();
+		if (lower === "http" || lower === "https") {
+			return `${lower}:`;
+		}
+	}
+	if (typeof req.scheme === "string" && req.scheme) {
+		const lower = req.scheme.toLowerCase();
+		if (lower === "http" || lower === "https") {
+			return `${lower}:`;
+		}
+	}
+	return undefined;
+}