Halfway through a pad thai or a Vietnamese dipping sauce and realised the fish sauce bottle is empty? Do not panic. Several storecupboard ingredients can stand in for it — and a couple of them are genuinely very close. Here are the swaps that work, in the order we would reach for them.
What is fish sauce?
Fish sauce (nam pla in Thai, nước mắm in Vietnamese) is made by fermenting fish — usually anchovies — with salt for months, then pressing and bottling the amber liquid. It smells pungent in the bottle but mellows completely in cooking, adding saltiness and a deep savoury flavour (umami) rather than anything overtly fishy.
It is the primary seasoning in Thai and Vietnamese cooking, used the way a Chinese kitchen uses soy sauce. Our fish sauce vs oyster sauce guide explains how it differs from its thicker cousin.
What fish sauce does in a dish
Three jobs: salt, savoury depth, and a faint sweet-fermented roundness. A good substitute needs to cover the first two at minimum — the third is a bonus. That is why plain salt alone always falls a little flat.
The best fish sauce substitutes
- Soy sauce — the best all-round swap. Use it one-for-one. Light soy sauce matches fish sauce's saltiness and adds umami of its own. The flavour is different (more beany, less marine) but in a cooked dish most people cannot tell. Add a squeeze of lime to get closer to fish sauce's brightness.
- Soy sauce plus a little vinegar or lime juice. Our favourite version for dipping sauces and dressings, where fish sauce's tang matters more. One tablespoon of light soy sauce plus a quarter teaspoon of rice vinegar or lime juice per tablespoon of fish sauce.
- Oyster sauce — for stir-fries only. Slightly sweet and much thicker, so use about two-thirds of the amount and thin it with a splash of water. Works well in cooked dishes; too thick and sweet for dressings.
- Worcestershire sauce. Made with anchovies, so it is closer in spirit than you might expect. Use half the amount — it is sharper and more vinegary. Fine in marinades and cooked sauces.
- Salt plus mushroom. For a vegetarian option, dissolve half a teaspoon of salt and a little finely crumbled dried shiitake (or a drop of mushroom soy sauce) in a tablespoon of warm water. Earthy, salty, savoury.
- Vegan fish sauce. Sold in many Asian grocers, usually made from seaweed, soy or mushrooms. Use one-for-one. Quality varies by brand, but the better ones are convincing in cooked dishes.
Vegetarian and vegan options
Traditional fish sauce is obviously off the table. In order of preference: a proper vegan fish sauce if you can find one; mushroom soy sauce (a dark soy brewed with straw mushrooms); or light soy sauce with a little lime juice. In soups and dipping sauces, a small piece of kombu (dried kelp) simmered in the liquid adds back some of that sea-derived savouriness.
When only real fish sauce will do
In dishes where fish sauce is the flavour rather than a background note, substitutes show their limits. A Vietnamese nước chấm dipping sauce, a green papaya salad, or a Thai larb will taste noticeably different made with soy sauce — fine, but not the same dish. For those, it is worth keeping a bottle in the cupboard. It lasts for years, costs a couple of pounds, and a little goes a long way.
Which fish sauce to buy
Look for a short ingredients list: fish, salt, and perhaps sugar or water. The first-press bottles are the cleanest-tasting. Two reliable options from the shelves at Tuk Tuk Mart:
The classic Thai bottle — balanced and not too aggressive. The 300ml size is ideal if you cook Thai or Vietnamese food occasionally.
View product →
A Thai kitchen workhorse at a better price per litre — the one to buy if fish sauce is a weekly ingredient in your cooking.
View product →You will find both in our Thai ingredients collection, alongside tamarind, palm sugar and curry pastes.
Fish sauce substitute FAQs
What is the best substitute for fish sauce?
Light soy sauce, used one-for-one. It covers the salt and the savoury depth. Add a squeeze of lime if the dish is a dressing or dipping sauce, where fish sauce's tang is more noticeable.
Can I use hoisin sauce instead of fish sauce?
We would not recommend it. Hoisin is thick, sweet and strongly spiced — it will change the character of the dish rather than quietly replacing the fish sauce.
Is fish sauce the same as oyster sauce?
No. Fish sauce is thin, salty and made from fermented fish; oyster sauce is thick, sweet-savoury and made from oyster extracts. They do different jobs — see our full comparison.
Does fish sauce need to be refrigerated?
No. Its salt content preserves it at room temperature. Keep it in a cool cupboard with the lid tight; it will last for years. The flavour is at its best in the first year or two.
Why does fish sauce smell so strong?
The pungent smell comes from the fermentation. It softens dramatically as soon as the sauce hits heat or is mixed with acid, sugar and other ingredients — the finished dish tastes savoury, not fishy.