It's a reasonable thing to wonder. You're considering getting into open water with an animal the size of a city bus, and someone is asking you to trust that it'll be fine. Here's what I'd tell you.

In the wild, outside of historical whaling contexts, there are no documented cases of a humpback whale harming a human swimmer. Not one. These are filter feeders — they eat krill and small fish by straining water through baleen plates. We are simply not something they're built to interact with aggressively.

What they actually do around people

Humpback whales in Tonga range from curious to completely indifferent to the humans floating near them. Mothers with young calves tend to keep their distance, which good guides read and respect. Resting whales often hold their position when swimmers enter the water nearby — not because they're welcoming you, but because they're relaxed enough not to care.

The calves are usually the curious ones. Young humpbacks will sometimes swim up toward a group of snorkelers on their own initiative, circling slowly before drifting back to their mother. Those are the encounters people can't stop talking about years later.

The risks that do exist

Being honest: the risks are real, but they're not the ones you're imagining. A humpback tail fluke spans 5-6 meters. When it moves through water, even slowly, it creates significant displacement. Being caught in that wash unintentionally is disorienting and can be physically forceful. Boat traffic around whale encounters presents risk if communication isn't tight. Cold and fatigue in open water are genuine considerations over a long week.

None of these are unique to whale swimming. They're the same risks as any open water activity, and they're managed the same way: experienced guides, small groups, clear protocols, and paying attention to what the animals are doing before anyone enters the water.

Why the safety record is strong

Tonga's permit system limits in-water encounters to four swimmers at a time per whale. That number exists for both ethical and safety reasons. Operators who've been running these trips for years have built their entire reputation on getting this right. They read animal behavior before every entry. They pull people from the water when something feels off. They don't take shortcuts because their business — and the continued permission to operate in this space — depends on doing it well.

What you actually need

You don't need to be a strong swimmer. Fins and a wetsuit provide significant buoyancy. You do need to be genuinely comfortable in the ocean — not panicked by open water, not someone who has never snorkeled before. If you can float calmly in the sea and breathe through a snorkel without anxiety, you have what's needed for this experience.

The moment a 15-meter whale drifts past below you in clear blue water, every concern you had about whether this was a good idea tends to evaporate. What replaces it is harder to describe, but most people who've done it say it's the closest they've come to feeling genuinely small in the world — and finding that completely, unexpectedly wonderful.