In Jain dharma, seaweed (nori, kelp, wakame, etc.) is generally allowed because:

• It is a plant/algae, not an animal.
• It is not a root vegetable, so it doesn’t fall under the usual kand‑mool restrictions.
• There is no specific Jain scriptural prohibition of seaweed the way there is for meat, eggs, honey, root‑vegetables, etc.

However, from the viewpoint of ahimsa:

1. Check ingredients carefully

- Many seaweed snacks or sushi sheets contain: - Fish powder / fish sauce - Shrimp or other sea “flavor” - Oyster sauce or bonito (fish) stock Any such products are not Jain‑acceptable.

1. Prefer plain, simple forms

- Plain dried or roasted seaweed without animal ingredients, alcohol, or fermentation is better. - Rinse well to reduce any tiny organisms or sand.

1. Special days / extra vows

- In periods like Paryushan / Chaturmas, if you have taken extra niyams (e.g., no green leafy vegetables, very simple food), you may choose to avoid seaweed too, according to your local tradition. - Always follow your own pachchakkhan (vows) and your guru / local sangh’s guidance.

1. Both Digambar and Shwetambar

- Both traditions focus on ahimsa and vegetarianism. - Seaweed is not singled out as forbidden; practice may vary by family and guru’s advice.

For a simple overview of what foods are acceptable to Jains, you can read more here

In summary: plain vegetarian seaweed, without any fish/egg/animal additives, is usually okay for Jains, unless your personal vows or local guidance say otherwise.