Olympic National Park is in two parts. There is the main park which dominates the peninsula and then there are the Pacific beaches. Some of these are tame, like La Push, a Quillayte fishing town, while others are wilder. There is a wilderness trail along the coast that runs from the northern most tip to Rialto Beach then resumes at Third Beach where it heads south to the Hoh River mouth. Route 110 leaves Route 101 just north of Forks and provides access to three of the more accessible beaches: Rialto Beach, Second Beach and Third Beach.
PACIFIC BEACH OPPORTUNITIES
Second Beach is reached from a parking lot on Quillayute land. The trail heads into the forest for 3/4 of a mile and then descends to the sea. There are magical sea stacks, a driftwood barricade, tidal pools, sea caves and a hole in the wall headland.
Third Beach requires a bit more walking, nearly a mile and a half, from the trailhead to the descent to the ocean. It is a slightly wilder trail, and the beach is just as wild. The beach has tide pools, headlands, sea stacks and a sense of the great ocean
Rialto Beach is the most accessible of the beaches in this area. You can drive right to the beach. The beach is easy going, but a mile north of the parking lot there is a river to cross, then come the tide pools and the headlands.
Cape Alava is reached via Route 112, but should be mentioned here. This is a total end of the earth experience. There is a three mile boardwalk from the trailhead to the sea, then three miles of beach with rocks and driftwood and fantastic sea stacks. This can be rough going. There is another three mile boardwalk back to the trailhead. This nine mile hike is an all day affair and should only be taken at low tide, ideally a low low tide of three feet or less. If you need more Pacific beach after visiting those others mentioned here or just want an overworldly challenge, consider a day at Cape Alave.
Ruby Beach and Klalaloch are more distant beaches, another 30 minutes drive past the Hoh Rain Forest turnoff. They are a bit far for the casual visitor, but there are cabins at Klalaloch, so if you have the time they are worth considering. (As always, in the summer, book early.)