Once the summer comes (usually by the end of April), a boat trip is an essential part of any sightseeing holiday to St. Petersburg. There's a huge choice of boats and operators, ranging from small private launches to multi-level river cruisers, so you can join a timetabled tour or organize your own if you're travelling in a small group. Nearly all boats, however, follow one of a few tried and tested routes along St. Petersburg's rivers and canals, as well as some longer routes out to the city's suburban visitor attractions. Inner-city tours start from around 400 rubles for adults (half-price for children under 12, and free for children under seven).