First of all, you may wonder if bike riding works on the beach. I wondered that too, but then I looked at some old pictures of my youngest boy on the beach, and one picture showed a family with bikes in the background. So I resolved to try it.
There is a strip of hard, flat sand just above the waterline. If you stay in that strip, the ride feels just like riding on asphalt. If you stray too close to the water or too high on the beach, the sand gets soft and the ride becomes arduous.
On this ride, I entered the beach down the Analyde Gap Road at the north end of Pacific Beach and rode north towards Moclips as far as I could go. The interesting things to see along this ride were: the sun rising above the cliff and obscured by the clouds, a mixture of seagulls and crows on the beach, the many beach houses in Moclips, and a flock of sandpipers dodging in and out of the surf.
After two miles, I reached the Moclips River, which runs too wide and deep to cross. Here the sand grew soft, so I parked the bike and walked along the river. Across the river the cliffside is completely undeveloped - compared to Moclips where it is lined with houses. Dozens of old, decaying posts are set in the river and the nearby beach. It looked like this may once have been a bridge across the river. Nearby I found a boundary marker for the Quinault Indian Nation. The reservation evidently extends a bit south of the river. You ordinarily need a beach pass to visit the QIN beaches, but I don't suppose anybody enforces that rule here.
More pictures found at: