There's nothing quite like the comforting aroma of a bubbling seafood casserole baking in the oven. The mix of tender shrimp, flaky white fish, and creamy, cheesy sauce creates a symphony of flavors that’s both indulgent and cozy.

I first threw this dish together on a chilly Sunday evening with whatever seafood I had in the freezer. What started as a spur-of-the-moment experiment quickly became a regular request at our dinner table. It’s quick, easy, and always a hit—especially when we’re craving something hearty but a little different from the usual casserole fare. Let me show you why this easy seafood casserole belongs in your weekly rotation.

Why You'll Love This Easy Seafood Casserole Recipe

Get ready to meet your new favorite comfort food. This easy seafood casserole is creamy, flavorful, and packed with delicious bites of the sea—all without requiring hours in the kitchen.

First, let’s talk about how quick it is. From prep to table, this dish takes about 40 minutes, making it a perfect weeknight meal when time is short but your appetite is big.

It’s also wonderfully budget-friendly. You can make it with frozen seafood mixes, pantry staples, and a few fresh ingredients—nothing fancy or hard to find. It’s ideal for feeding the whole family without breaking the bank.

Another bonus? It’s super versatile. You can mix and match seafood based on what you have available—shrimp, scallops, crab, or mild white fish all work beautifully. It's also a great way to use up leftover cooked rice or vegetables.

And if you’re feeding a crowd or prepping meals ahead, this casserole is freezer-friendly. Make it now, bake it later—it doesn’t get more convenient than that.

Now that you know why it’s a winner, let’s dive into what makes the ingredients in this dish so special.

Ingredients Notes

The beauty of this seafood casserole lies in its simplicity. It uses everyday ingredients that come together to create a comforting, satisfying meal with big coastal flavor.

Seafood is, of course, the star. I like to use a combination of shrimp and a flaky white fish like cod or haddock. Frozen seafood mix is also a great option—just be sure to thaw it and pat it dry before using to avoid excess moisture in the casserole.

Cream of mushroom soup adds the perfect creamy base without requiring a made-from-scratch sauce. It blends effortlessly with the other ingredients and helps hold everything together. You can swap in cream of celery or cream of shrimp for a twist.

Mayonnaise might sound unusual, but it brings a rich, tangy element that balances the creaminess of the soup. Combined with a touch of lemon juice, it brightens the dish and adds depth.

Shredded cheese, particularly cheddar or Monterey Jack, adds a gooey, golden topping and a mild sharpness that complements the seafood. Use freshly grated if possible—it melts better and has more flavor than pre-shredded.

Breadcrumbs give the top of the casserole a crispy, golden finish. Toss them in a little melted butter before sprinkling over the dish to make sure they brown evenly in the oven.

You won’t need any special equipment—just a standard 9x13-inch baking dish, a mixing bowl, and a spatula. Simple tools for a spectacular result.

How To Make This Easy Seafood Casserole

Making this casserole is a breeze, even on your busiest days. With just a bit of prep and one dish to bake, you’ll have dinner on the table in no time.

Start by preheating your oven to 375°F. If your seafood is frozen, make sure it’s fully thawed, drained, and gently patted dry with paper towels. This will help keep the casserole from becoming watery.

In a large bowl, combine your seafood, cream of mushroom soup, mayonnaise, lemon juice, and half of your shredded cheese. Gently fold the mixture together until everything is well coated and evenly combined.

Next, pour the seafood mixture into a greased 9x13-inch casserole dish. Spread it out evenly with a spatula, smoothing the top. Sprinkle the remaining shredded cheese over the top, followed by the buttered breadcrumbs.

Bake the casserole uncovered for 25 to 30 minutes, or until the top is golden brown and bubbly around the edges. You’ll know it’s done when the center is hot and the cheese has melted beautifully.

Let the dish rest for about 5 minutes before serving. This allows the flavors to settle and makes it easier to portion. From start to finish, you’re looking at around 40 minutes—a quick and delicious dinner that feels like a special occasion.

Storage Options

If you have leftovers, this seafood casserole stores beautifully. Simply cover the dish tightly with foil or transfer the remaining portions to an airtight container. It will keep in the refrigerator for up to 3 days.

For longer storage, you can freeze individual portions or the entire casserole. Make sure it’s fully cooled first, then wrap it well in plastic wrap and foil or place it in a freezer-safe container. It will keep for up to 2 months.

To reheat, thaw overnight in the fridge if frozen. Then, warm in a 350°F oven for about 15-20 minutes, or until heated through. You can also microwave single servings, but the oven gives the breadcrumbs a better texture.

Whether fresh or reheated, this casserole keeps its flavor and texture beautifully, making it perfect for meal prep or next-day lunches.

Variations and Substitutions

One of the best things about this easy seafood casserole is how customizable it is. You can change things up depending on your mood, what's in your fridge, or what’s on sale at the store.

Try using crab meat or scallops in place of the shrimp or white fish. These add a touch of sweetness and a different texture that pairs beautifully with the creamy base.

For a lower-carb version, skip the breadcrumbs and add extra cheese on top for a cheesy crust. You can also mix in cauliflower rice instead of traditional rice to cut down on carbs.

Want to sneak in some veggies? Add chopped spinach, peas, or sautéed mushrooms to the mixture before baking. It’s a great way to round out the dish and add color and nutrition.

If you’re dairy-free, use a non-dairy cream soup and vegan mayo and cheese substitutes. You’d be surprised how well these hold up in the oven and mimic the creamy texture.

Feel free to play around with seasonings too—Old Bay, garlic powder, a pinch of cayenne, or fresh dill can all take this casserole in different, delicious directions.

Don’t be afraid to make this recipe your own. With a forgiving base and endless variation options, it’s one of those dishes that gets better every time you tweak it.