Thai Sweet Potato Fish Cakes

Last updated on: September 15, 2026

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These Thai sweet potato fish cakes are a simple way to turn a couple of tins of tuna and a sweet potato into something considerably more exciting than yet another tuna sandwich.

Soft sweet potato keeps the middle tender, while tuna provides the bulk of the protein. Lime, spring onion, chilli, garlic and coriander give them plenty of fresh Thai-inspired flavour without requiring a cupboard full of specialist ingredients.

Each serving contains approximately 234 calories and 16 g of protein, with tuna providing the main protein hit. They’re particularly handy for lighter dinners, lunches and meal prep, or for anyone trying to keep calories sensible while still working towards their daily protein target. If fish regularly appears on your menu, you’ll find plenty more ideas in my high-protein fish recipes.

You’ll need a saucepan, mixing bowl, potato masher and a large frying pan. Prep takes around 15 minutes, followed by roughly 20 minutes of cooking.

Why you’ll love this high-protein recipe

• Each serving provides 16 g of protein for just 234 calories, making them an easy option when you want something filling without a massive calorie load.
• Tinned tuna keeps the recipe inexpensive, convenient and easy to make using ingredients available in pretty much any UK supermarket.
• The sweet potato gives the fish cakes a naturally soft centre without needing mountains of breadcrumbs.
• Lime, chilli and coriander give them plenty of flavour, so “healthy fish cake” does not translate to “sad beige hockey puck”.
• You can prepare the patties ahead of time and keep them chilled until you’re ready to cook.
• They work nicely as part of a calorie-controlled meal plan alongside plenty of vegetables or salad. You can find more ideas in my high-protein, low-calorie recipes.

What are Thai Fish Cakes?

Thai Sweet Potato Fish Cakes are a flavour-packed twist on traditional fish cakes, blending flaky tuna with mashed sweet potato and aromatic Thai-inspired ingredients. Unlike their breadcrumb-heavy cousins, these fish cakes get their soft texture from sweet potato, making them gluten-free (if you use GF breadcrumbs) and packed with nutrients.

The addition of lime, soy sauce, and chilli flakes gives them a slight heat and a zingy freshness, while a quick pan-fry in coconut or olive oil ensures a crispy, golden crust. They’re high in protein, easy to make, and ridiculously tasty—whether served as a main dish, a snack, or even meal-prepped for later.

Key Ingredients

Tuna. The main protein source in these Thai sweet potato fish cakes. Choose tuna in spring water or brine rather than oil so you’re not adding calories that don’t really bring much to the party.

Sweet Potato. This forms the base of the fish cakes and gives them a soft, slightly sweet centre. The important trick is draining it thoroughly after boiling so you don’t end up with wet, floppy patties.

Spring Onions. These add freshness and a gentle onion flavour without overpowering the tuna.

Lime Juice. A small amount makes a big difference, cutting through the sweetness of the potato and lifting the flavour of the tuna.

Soy Sauce. Adds saltiness and savoury umami flavour. You only need 10 ml, so don’t get carried away and turn the fish cakes into little soy sponges.

Chilli Flakes. One teaspoon provides a gentle kick. Reduce them for children or add more if your definition of “mild” is considerably more adventurous than everyone else’s.

Garlic. One clove adds background flavour without dominating the fish cakes.

Breadcrumbs. These absorb excess moisture and help bind everything together. Standard fresh or dried breadcrumbs both work well.

Fresh Coriander. Coriander brings the Thai-inspired flavour together nicely. Chop the stalks as well as the leaves because there’s loads of flavour hiding in them.

How to Make Thai Sweet Potato Fish Cakes

Add the peeled and chopped sweet potato to a large saucepan of boiling water. Cook for around 12–15 minutes, or until completely tender when pierced with a fork. Drain thoroughly and leave it to steam-dry for a few minutes so the fish cake mixture does not become soggy.

Add the drained tuna, panko breadcrumbs, chopped spring onions, coriander, garlic, chilli flakes and the remaining seasonings to a large mixing bowl. Stir everything together, breaking up any larger pieces of tuna with the back of a fork.

Mash the cooked sweet potato until mostly smooth, then add it to the tuna mixture. Mix thoroughly until all the ingredients are evenly combined. The mixture should hold together easily without feeling wet or sticky.

Divide the mixture into six equal portions and shape each one into a thick, round fish cake. Place them on a lined baking tray, then chill for around 20 minutes if you have time. This helps them stay together in the pan rather than staging a dramatic collapse.

Heat a thin layer of oil in a large non-stick frying pan over a medium heat. Cook the fish cakes in batches for 3–4 minutes on each side, turning carefully, until deeply golden and heated through. Serve hot with fresh coriander, lemon wedges and crunchy slaw.

Sweet Potato Fish Cakes Storage Tips

To Store

Allow the cooked fish cakes to cool completely, then place them in an airtight container in the fridge. They should keep well for up to 2 days.

If you’re making them ahead before cooking, shape the patties, cover them and refrigerate for up to 24 hours. Chilling them also helps firm them up, which makes flipping considerably less stressful.

To Reheat

Reheat the fish cakes gently in a frying pan over a medium-low heat for around 3–4 minutes per side until piping hot throughout.

You can also reheat them in an air fryer at around 180°C for 5–7 minutes. This is particularly good for bringing back a bit of crispness around the outside.

To Freeze

Freeze the shaped fish cakes before cooking for the best texture. Place them on a lined baking tray and freeze until firm, then transfer them into a freezer-safe container or bag with baking paper between the layers.

Freeze for up to 3 months. Defrost overnight in the fridge before frying as normal.

Serving suggestions

Serve these Thai sweet potato fish cakes with crunchy slaw, steamed greens, stir-fried vegetables or a large mixed salad.

A spoonful of Greek yoghurt mixed with lime juice and coriander makes a quick higher-protein dip. You could also serve them with jasmine rice if you want a more substantial dinner.

If you like the combination of fresh fish, rice and crunchy vegetables, my salmon poke bowl is another cracking option.

Thai Sweet Potato Fish Cakes

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These fish cakes are made with protein-packed tuna and sweet potatoes, combined with flavourful herbs and spices. They're crispy on the outside and tender on the inside, and make a great alternative to traditional fish cakes

• Total Time: 35 mins
• Yield: 6 1x

Ingredients

Units MUS Scale 1x2x3x

• 600 g sweet potato
• 2 cans (~145g each) of tuna in brine or springwater
• 4 spring onions, finely chopped
• 1 tbsp lime juice
• 10 ml soy sauce
• 1 tsp chilli flakes
• 1 garlic clove
• 80 g breadcrumbs
• fresh coriander, chopped
• black pepper
• 1 tsp coconut or olive oil

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Instructions

Peel, chop, and boil your sweet potatoes until they’re soft enough to mash. No one likes a crunchy sweet potato in their fish cake.

While they’re boiling, mix together the tuna, spring onions, lime juice, soy sauce, chilli flakes, garlic, breadcrumbs, coriander, and black pepper in a big bowl. Basically, throw everything in and pretend you're on MasterChef.

Once the sweet potatoes are done, drain and mash them. Then spread them out on a plate so they cool faster (because waiting is overrated).

When they’re cool enough to handle, mix them into your tuna mixture. Get your hands in there. It’s messy, but worth it. Form the mixture into six patties and set them aside.

Heat a little coconut or olive oil in a frying pan on low heat. Gently fry the fish cakes for 3-4 minutes per side until golden brown and crispy. Be careful when flipping—they’re delicate, like your ego after a bad haircut.

Serve with fresh coriander and lime wedges. And maybe some sweet chilli sauce if you’re feeling fancy.

• Author: Scott Baptie
• Prep Time: 15 mins
• Cook Time: 20 mins
• Category: Fish
• Method: Hob
• Cuisine: Thai

Nutrition

• Serving Size: 1 fish cake
• Calories: 234
• Fat: 6g
• Carbohydrates: 29g
• Protein: 16g

Recipe Video

Variations & tips

• Let the sweet potato steam-dry for a few minutes after draining it. Excess water is the number-one enemy of a fish cake that intends to remain a fish cake rather than become sweet potato scramble.
• For a higher-protein version, add another small tin of thoroughly drained tuna. You may need another tablespoon or two of breadcrumbs to keep the mixture firm enough to shape.
• Chill the shaped patties for 20–30 minutes before cooking if you have time. This makes them much easier to turn without breaking.
• Wet your hands very lightly before shaping the patties. The mixture sticks to your hands less, and you can form neater, more even fish cakes.
• Leave out the chilli flakes for younger children, then serve chilli sauce or sliced fresh chilli at the table for adults who want more heat.
• Prefer salmon? Try my air fryer Thai salmon parcels for similar lime-and-soy flavours with even less hands-on cooking.

Sweet Potato Fish Cakes FAQs

Why are my sweet potato fish cakes falling apart?

The most common culprit is too much moisture. Drain and steam-dry the sweet potato thoroughly, drain the tuna properly and allow the mash to cool before mixing everything together. Chilling the shaped patties before frying also makes a big difference.

Can I use normal potatoes instead of sweet potatoes?

Yes. Floury potatoes such as Maris Piper or King Edward work well and will usually produce a slightly firmer fish cake. The flavour will be less sweet, but the lime, chilli and coriander will still work brilliantly.

How can I make these fish cakes higher in protein?

You can add another tin of tuna to the mixture or serve the fish cakes with a Greek yoghurt and lime dip. Just remember that adding more tuna may mean adding a little extra breadcrumb to keep the patties firm.

Can I make Thai sweet potato fish cakes in advance?

Yes. Shape the patties and store them covered in the fridge for up to 24 hours before frying. In fact, a spell in the fridge helps them firm up and makes them easier to cook.

More high-protein recipes to try

• If you like quick fish dinners, try my Sweet Chilli Salmon – sticky, spicy and another easy way to get plenty of protein onto the dinner table.
• Fancy keeping the Thai flavours going? My Air Fryer Thai Salmon Parcels are fresh, zingy and involve very little washing up.
• For something fresh and colourful, try my Salmon Poke Bowl – a high-protein combination of salmon, rice and crunchy vegetables.
• Want a quick curry instead? My Prawn Curry is a simple one-pan dinner that’s ideal for busy weeknights.
• Craving something a bit creamier? My Tuscan Salmon delivers plenty of protein in a rich garlic and sun-dried tomato sauce.

Leave Me A Comment Below

As always, I would love to hear how you find this recipe. If you make it, please come back and leave a comment below. Thanks!