US Vs UK Filet-O-Fish: How Do They Differ?

When you compare how McDonald's most famous menu items are made from country to country, it's no surprise that you'll find some variations. Not only do international McDonald's menus have a lot of items we'd love to bring to the U.S., classics are also often prepared differently or available with more exciting side options. For instance, there are some major distinctions between the U.S. and U.K. Filet-O-Fish sandwiches (and meals) when it comes to toppings and customizations, which even include vegetarian and vegan substitutes.

In the United States, the McDonald's Filet-O-Fish is made from wild-caught Alaskan pollock. It's served on a steamed bun and topped with a slice of American cheese and tartar sauce. Said tartar sauce contains oil, pickle relish, egg yolks, onion, parsley, and other ingredients. When enjoyed as-is, the sandwich has 380 calories, 19 grams of fat, and 16 grams of protein. McDonald's in the U.S. also offers a Double Filet-O-Fish at select locations. 

The American Filet-O-Fish meal comes with fries and a drink; however, the sandwich and meal can be customized to an extent. For instance, you can upgrade it with extra sauce or cheese, add pickles or bacon, request shredded lettuce or sliced tomatoes, or even get mustard, ketchup, or mayo in addition to (or instead of) the tartar sauce. If you're ordering in person, you can swap the fries for apple slices and also try your luck with any number of delicious ways to customize your Filet-O-Fish sandwich.

It's no secret that McDonald's uses different types of fish for its Filet-O-Fish in some parts of the world. While U.K. McDonald's locations used to use hoki, the chain now uses sustainably caught pollock. It is sourced from fisheries that are certified by the Marine Stewardship Council (MSC), which is committed to protecting future fish stocks.

You can opt for a single or double Filet-O-Fish, each served on a steamed bun with tartar sauce made from oil, egg yolk, gherkins, mustard, capers, vinegar, onion, parsley and other ingredients. In addition to tartar sauce, it is topped with a slice of processed cheddar cheese. The sandwich on its own has 316 calories, 13 grams of fat, and 14 grams of protein, making it lower in fat, calories, and protein than the American version. The Filet-O-Fish meal comes with a drink, and you have a choice of fries, side salad, apple slices, or cucumber spears.

There's also a much wider range of customization options if you're buying a Filet-O-Fish sandwich in the U.K. Since the U.K. McDonald's menu includes vegetarian and vegan options, you can get the sandwich with a slice of vegetarian cheddar cheese or a vegan cheese alternative. You can also add ketchup or sandwich sauce, which is basically mayonnaise. McDonald's locations in the U.K. also have some condiments that are not offered in the U.S., including dips like Spicy Chili, Garlic Mayo, and Sweet Curry. In January of 2026, the chain also launched its first-ever official secret menu in the U.K. and Ireland featuring the Filet-O-Fish secret menu order that no one really likes: the Surf N' Turf burger.