I recently went there with my parents and we enjoyed watching the locks open/close, fill/empty and see the seagulls in action, eating. Be prepared for the stench when you walk over from the locks to the salmon ladder. We did see salmon in one ladder, but never saw one switch from one ladder to the next. The free visitor's center has a small amount of interesting exhibits (the hands-on ones all seemed broken), a small gift shop, and a short film.They offer free, guided tours, but we did not take one. If you park on the Ballard side of the locks you have to walk partially through the Botanical Gardens/park to get to the locks. The park was not crowded and it would be a good spot to have a picnic.
Pros: lots of different things to see (locks, ladder, park, visitor's center)
Cons: not easy for people who have a hard time walking far.
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