Ullswater is the second largest lake in the Lake District, stretching approximately seven miles in length. The lake has a right of navigation, meaning that once paddlers gain access to the water they are free to explore its full extent. Most of the lakeshore is private, which limits the number of public access points and makes knowing the launch locations particularly important for trip planning.

Several access points are available around the lake. Lay-bys opposite Sandwick provide lake access, and there is a public slipway near the steamer pier at Howtown Bay. Park Foot Holiday Park near Pooley Bridge offers parking and lake access for a fee, with launching available to non-residents for around £4.50 per day plus a parking charge. Waterside House Campsite on Howtown Road also provides lake access and canoe hire. The Gowbarrow National Trust car park near Glenridding is another option, though paddlers should be aware of swimmers and other water users in the vicinity.

The lake is home to char, perch, trout, and schelly — a freshwater herring and relic of the Ice Age found only in Ullswater, Haweswater, and three local tarns. The River Eamont, which connects to the lake, is a Site of Special Scientific Interest and Special Area of Conservation due to protected species including the rare white-clawed crayfish. Paddling on the Eamont is permitted only with prior permission from Dalemain Estates.

There is no requirement for boat insurance to launch on Ullswater, unlike Coniston and Windermere where insurance is checked before launching. Paddlers should be aware of other water users including swimmers, paddleboarders, and motorised craft, particularly near campsite access points.

A published Ullswater Canoe Trail provides route suggestions for one- and two-day trips. One recommended day route involves launching from the lay-bys opposite Sandwick, paddling to Skelly Nab and the Outward Bound centre, crossing the lake at its narrowest point to Geordie's Crag, making a short detour to the Birkett Memorial on Kailpot Crag, then paddling into Howtown Bay and across toward the steamer pier. The backdrop includes fells such as Helvellyn and Hallin Fell. Canoe, kayak, and SUP hire are available from multiple operators based at Pooley Bridge and along the lakeshore.