Useless Bay (shallow at low tide - Sunlight Beach may be a slightly better launch/landing than Double Bluff at low tide, although at lower tides it is also too shallow. Useless Bay gets its name from the shallow water that prevents boat access at low tide)
Double Bluff (has parking)
Double Bluff County Park at the north end of a very long Puget Sound Fetch to the south. paddle south and downwind back north to the park, popular with kiters (October is “Double Bluff” month)
downwind approx. 4 miles to Sunlight Beach (very limited parking) or 4.25 miles to Double Bluff Park
Mutiny Bay - boat ramp w/ spacious gravel parking lot. On a south wind you can probably do laps, protected by the shore going upwind then turn and downwind at some angle back into the bay, rinse and repeat, kind of like using an eddy to go upstream. You might get downwind legs up to almost 2 miles but you may lose some of your upwind return protection if you go that far north on your downwind legs in the Bay.
Admiralty Bay - similar in setup to Useless and Mutiny Bays.
Lagoon Point County Park to Driftwood Park 5.70 miles. Some variation of south wind? We need a report on this possible downwind run. Lagoon Point parking and beach access is “limited”. Is it okay enough for 1 or more surfskis to launch? How is Admiralty Bay?
East Side
Langley to Oak Harbor - 21 miles. We don't have a report of anyone doing this long of a Saratoga Passage downwinder. It could get somewhat exposed in the open water between Whidbey and Camano Islands well away from shore or you can take less of a direct line staying closer to the Whidbey shore along the way which would increase the trip length by about 1 mile. But in the right conditions (SE wind for one), might be a longer than usual worthwhile downwinder.
Langley - Port of South Whidbey Harbor has a boat ramp and beach access
Oak Harbor - Beach access at Flintstone Park
Alternate Put-ins/Take-outs
Penn Cove head west into this cove - protection from S, SE wind
North Side - Penn Cove Park 19.25 miles from Langley
South Side - Coupeville - Captain Coupe's Park and Boat Launch 19.5 miles from Langley
Hidden Beach - distance to Oak Harbor is about 11.5 miles. There is a parking lot with room for approx.15 cars but this is fairly remote and you will often not have anyone else around who might add some security for leaving your car here..