Shellfish and crustaceans are at the heart of Japanese dining — prawns at the tempura counter, crab in winter, scallops and clams in spring soups, the rotating cast of shellfish at a sushi counter. For a traveler with an allergy, two things make Japan harder than it looks. The labeling rules leave out several of the creatures you are most likely to meet. And in the kitchen, shellfish and crustaceans go into the stock, the frying oil and the chopping board, not only onto the plate.
Our group is involved in running restaurants in Tokyo, so this is written from the kitchen side.
What do Japan’s allergen labels cover — and leave out?
Japan’s Consumer Affairs Agency requires shrimp and crab to be labeled on packaged food, and recommends labeling for abalone and squid. The agency’s handbook for businesses defines these categories closely, and the definitions matter:
- “Shrimp” means decapods only. Prawns, shrimp, lobster and crayfish are covered. Mantis shrimp (shako), mysids and krill are classed as “other crustaceans” and are not covered. Shako is a classic Edo‑style sushi topping, often simmered and brushed with a sweet sauce.
- “Crab” covers the familiar crabs — king crab, snow crab, horsehair crab, swimming crabs and others.
- Abalone is the only shellfish on either list, and it is recommended, not required. The handbook excludes tokobushi, a smaller relative. Scallops, clams, freshwater clams (shijimi), hard clams (hamaguri) and oysters are on neither list.
- Squid of all kinds is on the recommended list. Octopus is on neither.
So even on packaged food in Japan, a label can be silent about mantis shrimp, scallops or oysters. And none of these rules apply to restaurant dishes: the agency notes that allergen labeling for restaurant and takeaway food is not mandatory.
Why can whitebait and clams carry shrimp or crab?
This is one of the least known points, and it comes from the agency’s own handbook. Whitebait (shirasu) and small dried sardines (chirimen‑jako) are caught with nets, and small shrimp and crab are sometimes caught with them. The handbook notes that these are hard to remove completely during processing and can end up in the final product. It gives example warnings for packaged goods, such as “caught by a method in which crab is mixed in”.
In a restaurant there is no such warning. Whitebait appears on rice bowls in coastal towns, on grated daikon as a side dish, in omelets and in the small plates at the start of a kaiseki course. If crustaceans are a serious problem for you, treat whitebait as a crustacean risk.
The same handbook notes two more routes. Clams such as asari and hard clams can have tiny pea crabs living inside them, which are hard to remove in processing. And fish paste, the base of fish cakes, can carry shrimp or crab in various ways, for example from fish that feed on shrimp. A clam soup can therefore be a crab risk as well as a shellfish one.
Where do shellfish and crustaceans hide in a Japanese kitchen?
What we see in restaurant kitchens, beyond the obvious prawn or crab on the plate:
- Stock. Shrimp heads and crab shells make rich stock for miso soup and sauces. Clam and freshwater‑clam soup is an everyday dish, and a clear soup of hard clams is a classic of spring. Dried scallop adductor and scallop extract season broths.
- Frying oil. At a tempura counter, prawns and vegetables go into the same oil, one after another.
- Mixed fritters. Kakiage, a fritter of mixed vegetables, often includes small shrimp or tiny sakura‑ebi.
- Fish cakes and crackers. Some fish cakes contain shrimp, and shrimp crackers (ebi senbei) are a familiar snack and bar nibble.
- Condiments. Dried sakura‑ebi and tiny shrimp or mysids appear in rice seasonings (furikake) and in tsukudani, sweet‑savory preserves served with rice.
- Sauces at a sushi counter. At some restaurants the sweet sauce brushed on simmered toppings is made from their cooking liquid. Ask what is in it.
What happens at a sushi or kaiseki counter?
One board, one knife, one pair of hands. At a sushi counter, the chef cuts every topping — tuna, prawn, mantis shrimp, scallop, clam — on the same board, often in front of you, and forms each piece by hand. A chef can leave shellfish off your plate. Most cannot promise that a piece of tuna has not touched the board where the scallop was cut a minute earlier.
The course is prepared before you arrive. At a set‑course restaurant, the stock, simmered dishes and sauces are made in the morning for everyone booked that evening. A clam stock that has been made cannot be taken out of the soup. When you tell the restaurant at booking, the cook can make your soup separately, plan a different course, or tell you honestly that the restaurant is not right for you.
“Shellfish” is not one word in Japanese. English uses shellfish for both crustaceans and molluscs. Japanese separates kai (shellfish with shells, such as clams and scallops) from ebi and kani (shrimp and crab). A kitchen told only kai may not think of prawns; one told only ebi may not think of mantis shrimp. Name each one.
How do I tell a restaurant in Japan?
Tell the restaurant when you book, and say which group and how serious:
| What to say | Japanese | Romaji |
|---|---|---|
| I have a severe allergy to shrimp, crab and other crustaceans, including mantis shrimp. | えび・かに・しゃこなど、甲殻類に重いアレルギーがあります。 | Ebi, kani, shako nado, kōkakurui ni omoi arerugī ga arimasu. |
| I am allergic to shellfish such as scallops, clams and oysters. | ほたて・あさり・かきなど、貝類にアレルギーがあります。 | Hotate, asari, kaki nado, kairui ni arerugī ga arimasu. |
| Is there any in the stock, the sauce or the frying oil? | だし・たれ・揚げ油にも入っていますか。 | Dashi, tare, ageabura ni mo haitte imasu ka. |
| Is there whitebait in any dish? | しらすやちりめんじゃこを使った料理はありますか。 | Shirasu ya chirimen‑jako o tsukatta ryōri wa arimasu ka. |
Say these lines when you book, and show the same words in writing when you arrive. Our free Japanese dining card sets out a shellfish or crustacean allergy for the kitchen, with the stock, the frying oil and the fish cakes noted, for you and everyone at your table.
A few practical notes:
- Choose the restaurant with the allergy in mind. A tempura counter or a sushi counter built around shellfish may be the wrong place for a severe crustacean allergy, however willing the chef.
- Accept an honest no. A chef who says the board cannot be kept separate is telling you something useful.
- Carry your own medication, and follow your doctor’s advice about traveling with it.
For how Japan labels allergens in general, and why a serious allergy has to be declared when you book, see our food allergy guide.
Before you go
If you want a restaurant to know all of this without a conversation in Japanese, the dining card puts it on one page for the kitchen. When we book for you, we pass this on to the restaurant in Japanese.
Sources
- Consumer Affairs Agency (消費者庁), 『加工食品の食物アレルギー表示ハンドブック（事業者用）』, April 2026 (令和8年4月): the scope of “shrimp” (decapods only; mantis shrimp, mysids and krill excluded) and of “crab”, p. 28; whitebait and small dried sardines caught with nets that also catch shrimp and crab, hard to remove in processing, with example warning labels; small crabs living inside clams such as asari and hard clams; shrimp or crab in fish paste; and the meaning of ami‑ebi, p. 27; the scope of abalone (tokobushi excluded) and squid (all squid), p. 30. https://www.caa.go.jp/policies/policy/food_labeling/food_sanitation/allergy/assets/food_labeling_cms204_260401_02.pdf
- Consumer Affairs Agency, “アレルギー表示について” (allergen labeling at a glance), as of April 2026: the nine mandatory and twenty recommended ingredients, which include abalone and squid but no other shellfish and no octopus; labeling applies to packaged processed food. https://www.caa.go.jp/policies/policy/food_labeling/food_sanitation/allergy/assets/food_labeling_cms204_260401_01.pdf
- Consumer Affairs Agency, report on promoting allergen information in restaurant and takeaway food, February 2023 (令和5年2月): allergen labeling for restaurant and takeaway food is not mandatory. https://www.caa.go.jp/policies/policy/local_cooperation/local_consumer_administration/advancedmodel/2022/assets/consumer_cooperation_cms201_230523_01.pdf
This guide describes labeling rules and kitchen practice. It is not medical advice; for a shellfish or crustacean allergy, follow your doctor’s guidance.
