The 100-yard rule covers a snorkeler as much as a tour boat. Federal regulation 50 CFR 216.19 makes it illegal to approach a humpback whale within 100 yards “by any means” anywhere within 200 nautical miles of the Hawaiian Islands, year-round. The sanctuary’s regulations page lists what that includes: a person in the water, standup paddleboards, kayaks, canoes, vessels and drones.
This page summarizes the regulation as published in the Electronic Code of Federal Regulations, checked on September 25, 2026, and the speed guidance that the sanctuary and the State of Hawaiʻi publish for boaters. It’s a plain-language summary, not legal advice, and we are an independent site, not NOAA or the sanctuary. The current text is at eCFR, 50 CFR 216.19.
What 50 CFR 216.19 prohibits
The regulation lists five acts, all within 200 nautical miles of Hawaiʻi. Four of them set distances. You may not operate an aircraft within 1,000 feet of a humpback, approach one within 100 yards by any means, or cause a vessel, person or other object to approach within 100 yards. You also may not intercept a whale: placing an aircraft, vessel, person or other object in its path so that the whale comes within 1,000 feet of the aircraft or 100 yards of anything else counts as an approach.
The fifth act has no distance. It’s illegal to disrupt a whale’s normal behavior or prior activity by any other act or omission. The regulation lists what disruption can look like: a rapid change in direction or speed, prolonged diving, underwater course changes or exhalation, evasive swimming, interrupted breeding, nursing or resting, a whale shielding a calf from a vessel or person with tail swishing or other protective movements, or whales abandoning an area they had been using.
Government vessels, personnel and assets are exempt when necessary for official duties, as are vessel operations needed to avoid an imminent and serious threat, vessels whose restricted ability to maneuver keeps them from complying, and activities under a NOAA Fisheries permit. Anyone who claims an exception has to prove it. Inside the sanctuary, a separate sanctuary regulation, 15 CFR 922.184, sets the same 100-yard and 1,000-foot limits.
If you see 50 CFR 224.103 cited for the Hawaiʻi approach rule, check the section number. In the current eCFR, paragraph (a) of 224.103 is marked reserved and paragraph (b) covers humpbacks in Alaska. The Hawaiʻi rule is 216.19, added in a 2016 rulemaking and amended in 2023.
Go Slow – Whales Below: speed guidance for boaters
“Go Slow – Whales Below” is a boating campaign, and its speed figures are recommendations, developed by the sanctuary with the State of Hawaiʻi Department of Land and Natural Resources, Pacific Whale Foundation and members of Hawaiʻi’s on-water community. They apply during whale season, November through May, in water 100 fathoms (600 feet) deep or less, where whales may be. The campaign poster says the guidance applies to drones and every kind of watercraft, down to paddleboards, kayaks, jet skis, eFoils and canoes.
The campaign’s one-page poster says to travel below 15 knots, or minimal planing speed, and to slow to 6 knots or less with no wake within 400 yards of a whale. The sanctuary’s boating page adds that you should leave at 6 knots or less until you’re more than 400 yards away, and the state’s boating division says to slow down further at night.
The poster labels two practices as the law. Don’t approach within 100 yards, and don’t leap-frog ahead or cut in front of a whale’s path. Under 216.19 that’s interception, illegal when it brings the whale within 100 yards. The rest is recommended practice: travel parallel to a whale and to the side and behind it, stay at the helm, and post a lookout in addition to the operator. The poster also warns that other boats may already have approached the same whales.
If a whale comes to you
Whales sometimes come within 100 yards of a boat or a person on their own. The sanctuary’s boating guidelines say to stop immediately if you find yourself within 100 yards of a humpback and to leave the engine running in neutral until the whale moves away. If whales are in your path, go around behind them while keeping more than 100 yards away, and never run out in front of them to get past.
The sanctuary’s recreation guidelines give the same advice to people without engines: if wildlife approaches you, stay calm and slowly back away, and don’t make sudden moves or block the animal’s path. On a kayak or paddleboard, make some noise now and then so whales know you’re there. Calves are especially vulnerable, because they are curious and may not yet be wary of boats.
Distances for other marine animals
For spinner dolphins, 50 yards is the law. Federal regulation 50 CFR 216.20, added in 2021, makes it illegal to approach or remain within 50 yards of a Hawaiian spinner dolphin by any means, or to swim within 50 yards of one, in waters within 2 nautical miles of the main Hawaiian Islands and in the waters between Maui, Lānaʻi and Kahoʻolawe. Its exceptions include a person who ends up that close by accident and moves away at once.
The sanctuary’s responsible recreation page gives viewing distances for the other animals Ocean Count volunteers log: 50 feet from Hawaiian monk seals and 10 feet from all sea turtles. It recommends binoculars, spotting scopes and zoom lenses for a closer look.
Reporting a violation or a whale in trouble
To report a close approach or another violation, call the NOAA Fisheries Enforcement Hotline at 1-800-853-1964. To report a collision or an injured, entangled or distressed whale, call the NOAA Marine Wildlife Hotline at 1-888-256-9840, or hail the U.S. Coast Guard on VHF channel 16 if you can’t call. The sanctuary asks for your contact details, the location and heading of the animal, and photos or video taken from at least 100 yards away.
Never try to free an entangled whale yourself or jump in the water to help. The sanctuary warns that people have died doing this, and asks anyone who can stand by safely to stay at a legal distance until a trained team arrives, since an entangled whale that nobody watches is usually not found again that day. Our whale watching overview explains how white flippers seen from shore get mistaken for netting.