What's the Difference Between Clams and Mussels?

Clams and mussels taste different, they look different, and they’re often prepared in different ways. Mussels show up in the beloved French dish moules mariniėre but aren’t typically called for in chowder, like clams are. Clearly, these shellfish are different. But how different are they when it comes to cooking? And most importantly, are clams and mussels interchangeable? 

Clams vs. Mussels 

First, let’s establish how clams and mussels are similar. They’re both bivalves, or mollusks that have two shells that open and close (like scallops and oysters). The other main category of shellfish is crustaceans, which have one shell and segmented limbs. Think crabs, lobsters, and shrimp.

Both clams and mussels can be found in saltwater and freshwater, and some (especially mussels) are farmed. Clams typically live in shallow water about two feet under the sand or mud. Mussels, meanwhile, cling to surfaces like ropes or, if they’re farmed, grow in tanks.

Clams and mussels are both relatively affordable, sustainable, and nutrient-dense options, which means they’re worth getting to know.

How To Tell Clams and Mussels Apart

Clams have rounder shells that are light gray or dirty white in color, while mussels have longer, more oblong-shaped shells that are dark blue or dark greenish-black.

What Do Clams and Mussels Taste Like?

Though varieties differ, clams are generally a little sweet, a little salty, and a little minerally. Their flavor reflects the water in which they grow. Depending on their size and where they grow, the level of sweetness, firmness, and brininess may differ. 

You don’t hear mussels described with such distinctions, perhaps because so many are farmed in more controlled environments that would leave them less susceptible to the fluctuations—and seasoning—of their natural environment.

Varieties of Clams and Mussels

While there are over 150 different kinds of clams, the edible varieties of clams that you’re probably most familiar are quahog, geoduck, manila, and soft shell clam. Northern quahogs—also known as cherrystone clams, littleneck clams, or hard-shell clams—have the familiar round, white shells. Geoducks, which can be found in both the Pacific and the Atlantic, have longer oblong shells. Manila clams are found in the Pacific and are smaller and sweeter than Northern quahogs. Soft shell clams, also called steamers, are found everywhere and have dirty white, oval shells.

There are to be many different species of mussels, roughly 17 of which are edible. Common varieties include blue mussels, which are in season in the winter and spring and have a strong flavor; Mediterranean mussels, which have large shells and plump meat; and New Zealand green-lipped mussels, which, as the name suggests, have green-tinted shells and are largely farmed in New Zealand. 

Can You Substitute Clams for Mussels and Vice Versa? 

The short answer is: pretty much. They do taste slightly different, especially if you’re comparing mussels to the sweet varieties of clams. So in that respect, they’re not completely interchangeable. But if you’re a fan of both and don’t have access to one, you can certainly swap in the other in a recipe and the cooking steps will be similar. As with all seafood, choose the freshest option.

How to Cook Clams and Mussels

When choosing clams or mussels, look for shells that are tightly sealed shut, which means the clams or mussels are still alive. If the shells are slightly open, give them a squeeze shut. If they don’t shut, discard them. However you’re applying heat, cook until the shells open, and that’s when you know they’re ready to eat. If a shell remains shut, discard. 

Just like the flavor will vary depending on the variety of clam or mussel, so too will the cook time. But generally speaking, all clams and mussels should cook quickly—within just a few minutes. The labor comes in before the actual cooking, in scrubbing and cleaning the shells and preparing the recipe’s ingredients. 

The most common way to cook clams and mussels is to steam them. Steam cooks gently, which is ideal for these soft-bodied shellfish. Steaming or cooking in low amounts of liquid also yields a delicious bonus because the resulting cooking liquid will be just as delicious as the shellfish itself. Searing or grilling these bivalves is also an option, but in all of these high-heat applications you’ll have to watch closely to make sure your shellfish doesn’t overcook and become tough and chewy.  

Recipes for Clams or Mussels (Or Both!)

• Seafood Paella
• Spaghetti with Clams
• Brothy Clams with Chorizo, Tomatoes, and Grilled Bread
• New England Cioppino 
• Steamed Mussels in Tomato Sauce
• Coconut Curry Mussels