We rented kayaks and paddleboards at Boating in DC – the Wharf Boathouse near L’Enfant Plaza. We had trouble finding the place, but we did (not by the other charter boats and not near the fish market). It's right by a splash pad which was great to cool off in. We could use the restrooms at the nearby restaurant or hotel. They had medium size lockers available - big enough for a backpack and they provided a lock. We were forewarned about starting the timer right away before you're out on the boat and being charged unfairly, but they were pretty relaxed and not particular with us - maybe because of previous reviews or maybe not a lot of people renting that time. Make sure to put enough sunscreen on and bring a hat if you're kayaking - there isn't shade on the river. The kids used paddle boards, 1 new and 1 somewhat experienced. The river was calm enough that our somewhat experienced child could teach the other. The guy who was by the boats hadn't paddle boarded before and could only instruct in theory. The boardwalk is hot, so apparently people usually walk down with shoes on, leave them there (not locked up) and then they have shoes to walk back in. We didn't know that and were okay down but had hot feet on the way back. As we are not big boaters, it was a little intimidating to be out on this wide river, but it wasn't too long before we were pretty comfortable. We should have brought water and light snacks in the double kayak. Fun thing to do.