Hawaii has no statute or rule that specifically allows or bans scattering ashes in bays, harbors or nearshore waters (inside 3 nm). The EPA general permit does not cover those waters, and no Hawaii agency was found that issues a permit for it. Hawaii's water quality rules (HAR 11-54/11-55, DOH Clean Water Branch) govern discharges to state waters in general, but no source says whether they reach a small ash scattering.

Because there is no permit path and a nearshore scattering falls outside the federal general permit, captains should go past 3 nm. Inside state harbors and boat basins scattering is not advisable. Also nearshore: Marine Life Conservation Districts (e.g., Molokini, Hanauma Bay) and the Kahoolawe Island Reserve (entry restricted, 2 nm around Kahoolawe) have their own access rules. Nolo says a DOBOR ocean event permit may be needed for large ceremonies on state ocean waters; DOBOR's marine event page says permits are reviewed case by case and gives no threshold, so this is unconfirmed.

In the ocean, cremated remains can be scattered at least 3 nautical miles from land, at any depth. No permit is needed in advance; the captain reports each scattering to the EPA within 30 days.

No extra state rules found. Hawaii has no state distance, notice or permit rule for scattering ashes at sea; the federal EPA rule (at least 3 nm from land) applies. Hawaii's own state ocean waters also run out to 3 nm, so a legal scattering is normally just outside state waters. Watch the inter-island channels: the Maui Nui channels (Pailolo between Maui and Molokai, Auau between Maui and Lanai, Alalakeiki between Maui and Kahoolawe) are only about 7-9 miles wide, so the middle can be barely 3 nm or less from BOTH shores. Measure from every piece of land, including Molokini, Kahoolawe, Lehua and other islets. Most of these waters (out to the 100-fathom line) are also inside the Hawaiian Islands Humpback Whale National Marine Sanctuary (15 CFR 922 subpart Q). The sanctuary bans 'discharging or depositing any material' (922.184(a)(5)), but the rule's 'provided that' clause limits the ban to activities that need a federal or state permit and are done without it or outside its terms; scattering that fully complies with the EPA general permit appears to be allowed, but NOAA has not confirmed this in writing (see open questions). Inside the sanctuary, never approach within 100 yards of a humpback whale (922.184(a)(1)); in season (roughly November-May) that is a real issue during a slow drift ceremony. Federal rules also bar approaching Hawaiian spinner dolphins within 50 yards within 2 nm of the main islands (50 CFR 216.20). A 2000 Honolulu Star-Bulletin column quoting DLNR boating staff said remains should be scattered beyond 3 nm and that the Health Department requires no environmental permit to scatter on land, sea or from the air (secondary source).

We couldn’t confirm these from official sources yet. Ask the agency before relying on them.