What to eat with shellfish allergy?

Going to travel to Japan with someone that is allergic to basically any kind of shellfish: shrimp, lobster, octopus, crab, etc. He can eat fish fine and likes it, but anything else he must avoid. His allergies aren't that severe but we will still have an allergy card to show at restaurants, but to be safe we wanted to know what kinds of food to avoid there in general if possible.

We already have crossed out tempura, takoyaki, ramen and other dishes with broth. Apparently okonomiyaki isn't safe either, is that correct?

Any tips and recommendations are good really. In particular, I really want to try many different Japanese dishes so I want to find a way where I can enjoy lots of great food of all kinds while he can enjoy as well with his restrictions.

「We already have crossed out tempura, takoyaki, ramen and other dishes with broth. Apparently okonomiyaki isn't safe either, is that correct?」

If your friend is allergic to octopus then yes, you will need to avoid takoyaki, since they are octopus dumplings. However, there are many kinds of tempura and ramen, as well as various Japanese broths, that do not contain any shellfish. Okonomiyai also does not always contain shellfish, as it's a kind of crepe that various ingredients can be used for.

It would take much longer to list all the types of Japanese food that don't contain shellfish than the ones that do. Perhaps if there is a specific dish you're interested in, we could help you determine whether or not it contains shellfish.

Went to Japan with shellfish and meat allergies. Breakfast would usually be onigiri or bread, Onigiri packs have English labels on them. Lunch or dinner would be sushi, sashimi or veggie curry; dango for snacks.

There are still lot of food options even with dietary restrictions. Have fun!

Is the issue cross contamination? If so, then that would rule out some of the items on your list like tempura. But, there are a ton of other foods that get nowhere near shellfish or even fish in general. It is not hard to find options.