The San Juan Islands, located 140 km north of Seattle in the heart of Salish Sea, is the most famous place for orca whale watching. Orca whales usually pass through the islands in greatest numbers between mid-May and mid-October when the salmon runs are strongest, although it's possible to spot them through the rest of the year. In February, March, April, late October, and November you can see 50% fewer whales than in the summer. However, keep in mind that every year is different depending on the ecosystem.
While on the tour you can also expect to see Humpback Whales and Minke Whales, as well as sea lions and seals. Gray Whales can be spotted near Whidbey Island. There is also the scenic Deception Pass, which is worth exploring. Bald Eagles, porpoises, and other interesting seabirds inhabit the islands and are easily spotted near the shore.
Also, whale watching tours depart from the city of Anacortes located on Fidalgo Island, east of the San Juan Archipelago. Orca tours are offered between mid-February and November, while humpback whales, grey whales, and minke whales may be spotted throughout the year.
From March to May, you can also hop on one of the whale watching tours from Everett to spot majestic gray whales. Puget Sound waters teem with wildlife that attracts these mammals close to the shore.