Ingelbert
Kayaking is awesome in the San Juans, but you probably know that already.
If you're on Orcas, go see Shearwater Adventures or BodynBlade for water conditions. Deer Harbor islands are great. If you're on San Juan Island, go to Lime Kiln Point to see the Orcas swim by. If you're on Lopez, paddle off of Spencer Spit or MacKaye Harbor (go around Iceberg Point but watch conditions). Seattle- Lake Washington, and lots of Puget Sound areas.
I've been to the San Juans twice. Lime Kiln is the perfect whale spotting place! The first time I was with a group of teenagers (I was 16.) We were kayaking in Haro Strait and a pod of orcas approached. We stopped paddling and just drifted. An adult male came straight at our kayak and dove right under us! We could have probably touched his dorsal fin with our paddles. We looked under the kayak as he went under and we could see his saddlepatch so clearly. It was one of the most amazing experiences!
The second time I went with my husband. We went kayaking on the other side of the island because DH is afraid of animals in the water, and my story about the orca scared him. Instead, we ended up getting surrounded by curious seals who came within 20 feet of the kayak as we drifted there for a half hour. I will never forget the look on his face as DH clutched the paddle and said, "I don't care about a no-paddling rule, we need to get out of here before they try to knock us over!" Yes, irrational, but to this day he swears they were going to eat us. They did finally leave us alone, but there was one that followed us for quite a while popping out of the water, looking at us, then silently going back under.