Swordfish is a high-protein fish. A 3-ounce cooked serving delivers about 20 grams of protein for just 146 calories, making it one of the more protein-dense options at the seafood counter. That single serving covers 40% of the daily recommended protein intake.
Protein and Calorie Breakdown
A 3-ounce portion of cooked swordfish (roughly the size of a deck of cards) contains 19.9 grams of protein, 6.74 grams of fat, and 146 calories. That works out to about 55% of its calories coming from protein, which puts it in strong company among animal protein sources. For anyone tracking macros or trying to hit a protein target without excess calories, swordfish delivers efficiently.
Swordfish is also a complete protein, meaning it contains all nine essential amino acids your body can’t produce on its own. Leucine, the amino acid most closely linked to muscle repair and growth, makes up roughly 8.7% of the total amino acids in swordfish muscle. That’s a notable concentration, since leucine is the primary trigger for muscle protein synthesis after a meal.
How It Compares to Other Fish
Swordfish holds its own against the most popular high-protein fish, though it doesn’t top every list. Here’s how a 3-ounce cooked serving stacks up:
- Cooked skipjack tuna: 24g protein per 3 oz
- Canned white tuna (in oil): 22.6g protein per 3 oz
- Canned sockeye salmon: 22.4g protein per 3 oz
- Swordfish: 19.9g protein per 3 oz
- Canned Atlantic cod: 19.3g protein per 3 oz
- Raw farmed Atlantic salmon: 17.4g protein per 3 oz
Tuna varieties tend to edge out swordfish slightly in raw protein per serving, especially skipjack and bluefin. But swordfish is comparable to canned salmon and cooked cod, and it outperforms raw salmon fillets on a per-ounce basis. The differences are small enough that choosing between these fish usually comes down to taste, price, and how often you eat them.
Other Nutritional Benefits
Beyond protein, swordfish is an excellent source of selenium. A single 3-ounce serving provides 58.2 micrograms, which exceeds the daily recommended intake of 55 micrograms for most adults. Selenium supports thyroid function and acts as an antioxidant, protecting cells from damage.
Swordfish also provides omega-3 fatty acids, though in moderate amounts. A 3-ounce serving contains roughly 0.2 grams of combined EPA and DHA (the two omega-3s most beneficial for heart and brain health). That’s lower than what you’d get from salmon or mackerel, so if omega-3s are your primary goal, swordfish isn’t the strongest pick. It’s a solid secondary source, though, especially if you’re eating it regularly alongside fattier fish.
The Mercury Tradeoff
Swordfish sits in the highest mercury category on the FDA’s advisory chart. Mercury accumulates in large, long-lived predatory fish, and swordfish checks both boxes. For most healthy adults, an occasional swordfish steak isn’t cause for concern. But eating it multiple times a week could push mercury exposure to levels that affect the nervous system over time.
People who are pregnant, breastfeeding, or feeding young children should avoid swordfish entirely, according to the FDA’s current guidance. For everyone else, treating swordfish as an occasional protein source rather than a weekly staple is the practical approach. Rotating it with lower-mercury, high-protein fish like salmon, cod, or skipjack tuna lets you get the protein benefits without the accumulation risk.
Making the Most of Swordfish as a Protein Source
Swordfish’s firm, steak-like texture makes it one of the easiest fish to grill, sear, or broil without it falling apart. That dense texture comes from its tightly packed muscle fibers, the same structure that makes it so protein-rich. A 6-ounce portion, which is a typical restaurant serving, delivers close to 40 grams of protein, enough to anchor a meal without needing additional protein sides.
Because swordfish carries more fat than ultra-lean fish like cod or tilapia, it stays moist during cooking and doesn’t need heavy sauces or breading to taste good. That’s a practical advantage if you’re trying to keep a meal high in protein without adding extra calories from coatings or condiments. A simple preparation with olive oil, lemon, and seasoning keeps the nutritional profile clean while letting the natural flavor come through.