How to Cook Seafood on a Charcoal Hibachi Grill (Fish, Prawns & More)

Most people treat charcoal as a meat thing. They're missing half the game.

Seafood over charcoal is extraordinary — and in many ways it's simpler than cooking meat. Fish cooks fast. Prawns take three minutes. Scallops take less. The charcoal delivers a smokiness that complements seafood in a way that gas just can't replicate, and the direct high heat caramelises the natural sugars in shellfish and fish skin in a way that makes everything taste like it was prepared by someone who knows what they're doing.

The challenge with seafood on charcoal is mostly about heat and sticking. Get those two things right and everything else follows.

The Fundamentals

Heat Management

Seafood likes medium-high heat — around 250–350°C at grate level. Less aggressive than the 400°C+ you'd use for steak. Too hot and the skin burns before the flesh cooks through. Too cool and the fish steams instead of grilling, and you lose the crust you're after.

After pouring your chimney, let the coals spread and settle for 5–10 minutes. If the grates are red-hot, elevate the food away from the coals by using a folded layer of foil as a buffer, or just let more time pass.

For grills with adjustable grate height — like the hydraulic adjustable WillBBQ portable grill — raise the grate slightly for seafood compared to your steak position. More distance from coals = gentler heat.

The Sticking Problem (And How to Solve It)

Sticking is the reason most people don't cook fish on a BBQ. Here's the full solution:

1. The grates must be screaming hot before food touches them. A grate that's only warm will grab onto protein. A grate that's properly hot will create a quick crust that naturally releases. Don't rush it onto a cold or warm grill.

2. Oil the grates immediately before cooking. Paper towel on tongs, dipped in canola or rice bran oil, wiped across the grates right before the fish goes on. Do this with the grill at cooking temperature — the oil polymerises instantly and forms a non-stick surface.

3. Oil the fish, not just the grates. Brush the fish (skin and flesh) with a high smoke-point oil before it goes on.

4. Don't force it. This is the biggest one. When fish is ready to flip, it will release. When it's not ready, it sticks. If you put light pressure under a fish fillet with a spatula and it resists — let go and wait 30–60 more seconds. It will tell you when it's ready.

5. A dedicated fish spatula. A wide, thin-bladed spatula designed for fish gives you more surface area to get under a whole fillet without it breaking apart.

Seafood by Seafood: How to Cook It

Whole Fish (Snapper, Bream, Barramundi)

A whole fish over charcoal is one of the great Australian BBQ experiences. The charcoal smoke penetrates through the cavity, the skin crisps up beautifully, and you end up with something that's hard to recreate indoors.

Best fish: Snapper, bream, barramundi, whole mackerel, trout. Anything from 400g to 1kg fits well on a hibachi grill. Larger than 1kg and you either need more grill real estate or to cook it in halves.

Prep: Scale and gut the fish if your fishmonger hasn't already. Pat completely dry inside and out — moisture is the enemy of crispy skin. Score the skin 2–3 times on each side (cuts through to the bone), which helps the flesh cook evenly and lets the seasoning penetrate. Fill the cavity with a few lemon slices, a sprig of herbs (thyme or dill), and a pinch of salt.

Season: Salt the outside generously. Oil the skin. That's all — charcoal does the rest.

Cook: Start skin-side down over medium-high heat. For a 600g fish: 5–6 minutes skin-side, then flip carefully with a wide spatula and cook a further 4–5 minutes. The fish is done when the flesh flakes at the thickest point and the eyes have turned opaque white.

Tip: A fish basket (wire clamp) is worth having for whole fish — it makes flipping much simpler and prevents skin sticking to the grates when you turn. Available at most kitchenware stores for under $20.

King Prawns

If you've never done king prawns over live charcoal, fix that this weekend. Butterflied in-shell prawns over high heat, with the shell protecting the flesh and crisping at the edges — they take three minutes and taste like they came from a $100/head restaurant.

Buy: Fresh, not frozen if possible. Head-on. Shell-on. Bigger is better — size 8–12 (8–12 per kg) gives you more flesh to work with.

Prep: Using kitchen scissors, cut along the back through the shell from head to tail. Don't cut through. Open the prawn slightly (butterfly), devein by pulling out the dark vein, and press flat. Season with salt only.

Cook: Shell-side down first, over high heat. 2 minutes. Flip, flesh-side down for 60–90 seconds. Done when the flesh has turned opaque and pulls away from the shell slightly at the edges.

Serving: Squeeze of lemon. Garlic butter on top as they come off the grill. A small bowl of aioli if you want something to dip into.

Scallops

Scallops are one of the fastest and most rewarding things you can grill. Over charcoal, you're aiming for a caramelised golden crust on one side and a just-set, translucent centre. The entire cook takes about 3 minutes.

Buy: Large scallops (anywhere from 10–20 per kg). In-shell is spectacular for presentation — the shell acts as a natural cooking vessel and you serve and eat straight from it.

Prep (no shell): Pat completely dry. Very dry — any surface moisture and you'll steam them instead of searing. Season with salt only just before they go on.

Prep (in-shell): No seasoning needed before cooking. A drop of soy and butter goes in the shell at the end.

Cook (no shell): High direct heat. Flat side down (the flatter, rounder side). Don't touch them. 90 seconds on one side until golden-brown and caramelised. Flip, 45–60 seconds on the second side. Off the grill.

Cook (in-shell): Shell-side down on the grill, 3 minutes. In the last 30 seconds, add a small cube of butter and a drop of soy or mirin. Serve in the shell.

Don't overcook scallops. They should still have a slight translucency in the centre. Once fully cooked through, they turn rubbery within minutes.

Calamari and Squid

Calamari is brilliant on charcoal but can go wrong quickly — it's one of those proteins that's perfect at under 2 minutes or over 20 minutes, and rubbery in between. For hibachi, you want fast and hot.

Buy: Fresh squid or calamari from a fishmonger — cleaned bodies and tentacles. If buying tubes, cut open and lay flat for the most contact with the grates.

Prep: Score the inside of the tube in a crosshatch pattern — this helps it curl attractively and cooks more evenly. Lightly oil. Season with salt and pepper.

Marinade option: Equal parts soy, rice wine vinegar, and sesame oil — marinate for 30 minutes before cooking for an Asian-style flavour.

Cook: Very high direct heat. Scored-side down first, 60–90 seconds maximum. Flip, another 60 seconds. Tentacles can go alongside for 2–3 minutes, turning once.

Serving: Charcoal-grilled calamari with a squeeze of lemon and fresh chilli is phenomenal. Simple works here.

Corn and Lemon as Sides

While you're there with fresh charcoal — corn on the cob, halved, 10 minutes of rotation over the coals, produces the best corn you'll eat all summer. Cut lemons face-down on the dying coals for 2 minutes produce charcoal-caramelised citrus that goes with absolutely every piece of seafood above.

These two things take no extra time and make the whole spread better.

Marinades and Sauces

Simple Charcoal-Friendly Marinade (works on most seafood)

• 2 tbsp olive oil
• 1 tbsp lemon juice
• 1 clove garlic, grated
• Salt and white pepper
• Marinate 30 minutes max — acid in the lemon starts "cooking" the seafood if left longer

Japanese-Style Glaze (for prawns and scallops)

• 2 tbsp soy sauce
• 1 tbsp mirin
• 1 tsp sesame oil
• 1 tsp grated ginger
• Brush on in the last minute of cooking

Garlic Butter (finish everything with this)

• 60g butter, softened
• 2 cloves garlic, minced fine
• 1 tbsp chopped flat-leaf parsley
• Salt to taste
• Drop a small cube on anything as it comes off the grill

Which WillBBQ Grill for Seafood?

Final Word

Seafood on charcoal requires confidence with heat and timing — but the fundamentals are learnable in one or two cooks. The payoff is extraordinary. A whole snapper off live coals, rested for two minutes and served with charcoal-caramelised lemon, costs $25 and tastes better than anything you'll find in most restaurants.

Get the grill hot, get the grates oiled, don't force the flip, and keep it simple. That's the whole secret.

WillBBQ hibachi grills are built for exactly this kind of cooking — available in tabletop to commercial sizes, all free shipping (over $50) in Australia. Browse the range.