Check the tide tables available at many stores and visitor's facilities along the Oregon Coast. At low tide, ramble the basalt rock gardens at Yachats State Recreation Area or Cape Perpetua National Scenic Area. Look for starfish, urchins and crabs. Always keep a close eye on the breakers, though; never allow yourself to be stranded by the incoming tide.
Cape Perpetua to Yachats's immediate south offers innumerable and breathtaking hiking opportunities. Head for the top of the Cape for incredible views ocean-ward, or stick closer to shore for evocative displays of surf and rock: the Devil's Churn or the Spouting Horn. Just inland, the Cummins Creek Wilderness--accessed by a trail along an abandoned road--beckons with its old-growth temperate forest.
With the appropriate permit, you can forage for ocean foods along the public beaches. For example, one can catch shellfish and ghost shrimp. Comb the Siuslaw National Forest for mushrooms; harvesting under a gallon per day is considered incidental use, and it doesn't require a permit. However, only six can be matsutake, and those must have a ½-inch or more of their stem immediately cut off). Pick huckleberries without any repercussions.
The Oregon Coast is famous for its fantastic whale-watching opportunities, especially during the winter and spring migrations of gray whales. Some 18,000 grays pass offshore twice a year on their tremendous journeys between Bering Sea summer feeding grounds and the Baja lagoons where they calve. Cape Perpetua is one of the coast's great vantages; look for spouts to key into traveling whales. Don't stop looking outside the migration months; there are typically 200 to 400 gray whales that summer off the central coast, often feeding very near the shore.
When you need a breather from salt-sprayed tide pool rocks or fog-bound Coast Range forest, head back to town to sample Yachats' impressive culinary options. Enjoy the fine cuisine and atmosphere at the Green Salmon cafe; in the evening, see if live music's on the menu at the Drift Inn or the Landmark Restaurant. During the summer, a lively farmer's market features produce and crafts on Sundays. Hole up in one of the town's inns to cozily observe the Oregon Coast's tempestuous winter storms.