Canoeists will discover several excellent places to paddle within Grand Teton , particularly the Snake River Oxbow Bend , String Lake, and Leigh Lake. Canoes are available for rent both in the park at Colter Bay Marina and Signal Mountain Lodge and in Jackson.
Boaters within Grand Teton will need to buy a permit; seven-day permits cost $20 for motorboats, $10 for nonmotorized craft. Motorboats are allowed only on Jackson Lake , Jenny Lake  (10-horsepower max), and Phelps Lake. Sailboarding, water-skiing, jet skis, and sailing are permitted on Jackson Lake, but no personal watercraft are allowed anywhere in the park.
All boaters must purchase an Aquatic Invasive Species decal ($10), and must take precautions to protect waterways from the spread of potentially ruinous nonnative plants and animals. Details are available online (www.cleaninspectdry.com , www.protectyourwaters.net ).
Jenny Lake Boating (307/734-9227, www.jennylakeboating.com ) has a variety of services on the south end of this gorgeous, mountain-rimmed lake, including shuttle boats ($10 adults, $5 kids) to Inspiration Point, one-hour scenic boat cruises ($15 adults, $7 kids), and rentals of canoes and tandem kayaks ($15 per hour). The boats run daily mid-May-September.
Jackson Lake has three marinas, all of which are generally open mid-May-late September. Signal Mountain Lodge Marina (307/543-2831, www.signalmountainlodge.com ) rents a range of floating vessels, including sea kayaks, canoes, motorboats, runabouts, fishing boats, pontoon boats, and deck cruisers.
Colter Bay Marina (307/543-3100 or 800/628-9988, www.gtlc.com ) is near a Park Service campground, cabins, and the Colter Bay Visitor Center. It’s an exceptionally busy place in the summer, with motorboat, kayak, and canoe rentals, along with guides to take you to the hot fly-fishing spots. Scenic Jackson Lake cruises ($26 adults, $13 kids under 12) are also available from Colter Bay Marina, as are breakfast or evening cruise-and-dine trips ($36 adults, $22 kids for breakfast; $57 adults, $37 kids for dinner).
O.A.R.S. (209/736-4677 or 800/346-6277, www.oars.com ) offers multi-day sea kayaking trips around Jackson Lake —perfect for beginning kayakers and families. You don’t need any paddling experience for these trips, which are supported by a motorized skiff. Overnight trips cost $265 for adults or $215 for youths; two-night kayak trips are $422 adults or $340 kids. O.A.R.S. also has combination trips that include kayaking on the lake and rafting down the Snake River; a three-day multi-sport trip costs $659 adults or $554 youths. For the whole enchilada, check out their six-night combo trips that include kayaking on Yellowstone and Jackson Lakes, park tours, camping, and a raft trip down the Snake River for $1,539 adults, $1,385 youths. The company supplies kayaks, a guide, tents, and dry bags, with sleeping bags available for rent. Reserve several months ahead, since these popular adventures fill quickly.
Jenny Lake Boating (307/734-9227, www.jennylakeboating.com ) rents canoes and tandem kayaks for $15 per hour. Canoes are also available at the Signal Mountain and Colter Bay marinas.