Kenai Fjords is essentially a marine park. On a boat tour, you'll see its mountains, glaciers, and wildlife, including sea otters and sea lions, and, depending on the season, conditions, and luck, humpback whales, orcas, mountain goats, and black bears. Gray whales come in the early spring, and huge fin whales show sometimes, too, but are hard to see. Bird-watchers may see bald eagles; puffins (both tufted and horned); murrelets (marbled, ancient, and Kittlitz's); cormorants (red faced, pelagic, and double-crested); murres (common and thick billed); auklets (rhinoceros and parakeet); and various other sea ducks, alcids, and gulls.

The farther you go into the park, the more you'll see. If you really want to see Kenai Fjords National Park and glaciers that drop ice into the water, the boat has to go at least into Aialik Bay to Holgate Glacier or Aialik Glacier. Northwestern Glacier is even deeper in the park. Half-day Resurrection Bay cruises offer plenty of impressive scenery but pass only one large glacier, and that at a distance. They have less chance of seeing whales and see fewer species of birds. The longest trips into the heart of the park encounter the greatest variety and number of birds and animals. If you're lucky with the weather, you can make it to the exposed Chiswell Islands, which have some of the greatest bird colonies in Alaska, supporting more than 50,000 seabirds of 18 species. I've seen clouds of puffins swarm here. The day-long trips also allow you more time to linger and really see the behavior of the wildlife. Whatever your choice, binoculars are a necessity, but if you didn't bring your own, you can often rent them onboard.

Prices are around $170 to go to Northwestern Glacier in Northwestern Fjord off Harris Bay, a 10- to 12-hour trip; $140 to $160 to go to Holgate or Aialik Glacier in Aialik Bay, which takes 6 to 8 hours (the most common destinations); and $60 to $90 for a 3- to 5-hour Resurrection Bay tour, which doesn't go to the national park at all. Children's prices are around half off. If publicity material from a tour operator is vague or confusing, ask exactly where the boat goes or get a map of the route. Bear Glacier, within Resurrection Bay, is unimpressive, because boats can't get close to it. You have to go at least to Aialik Bay for a noteworthy glacier encounter.

The season begins in April with tours to see the gray whale migration, mostly within Resurrection Bay. That's done by mid-May, when the regular schedule of tours begins, which lasts into September. Fares with each operator differ little, although you can sometimes get early season or Web specials; instead, shop for the destination, length of trip, food service, interpretation, and size or intimacy of the boat. Consider the seating arrangement. How many passengers will be onboard? Is lunch provided, and what does it consist of? Another important point of comparison is whether you have a ranger doing the commentary or the captain -- some of these captains don't know when to shut up, and they can give inaccurate information.

Try to schedule loosely so that if the weather is bad on the day you choose for your boat trip, you can wait and go the next day. If the weather's bad, you'll be uncomfortable and the animals and birds won't be as evident, or the boat may not go out of Resurrection Bay. If you pay upfront to hold a reservation on a boat -- probably a good idea in the busy season -- find out the company's refund and rescheduling policy.

Most operators offer packages with the Alaska Railroad and the SeaLife Center, or even with a local hotel, which may save money, but make sure you have enough time to do everything you want to do in Seward. All have offices at the Small Boat Harbor in Seward. Here are some of the best.

It's Not Easy Being Green -- A critical factor in choosing your boat tour is your susceptibility to seasickness. To reach the heart of the park, vessels must venture into the unprotected waters of the North Pacific. Large, rolling waves are inevitable on the passage from Resurrection Bay to the fjords themselves, although once you're in the fjords, the water is calm. On a rough day, most boats will turn back for the comfort of the passengers and change the full-day trip into a Resurrection Bay cruise, refunding the difference in fare. Of course, they'd rather not do that, and the decision often isn't made until the vessel is out there and some people are sick. If you get seasick easily, my advice is to stick to the Resurrection Bay cruise or take a boat tour in protected Prince William Sound, where the water is always smooth, from Whittier or Valdez.

Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.