This April marks the peak season of one of the region’s most unusual natural spectacles, when thousands of silvery fish will briefly leave the Pacific and shimmer across the shoreline under the night sky. Next week, grunion will emerge from the ocean in a rare spawning ritual that turns the sand into a “living, moving surface” called Grunion Run.
Found only along the coasts of SoCal and northern Baja California, Mexico, this phenomenon is so precisely timed that it can be predicted months in advance, according to the California Department of Fish and Wildlife. Unlike most fish, grunion (Leuresthes tenuis) reproduce entirely out of water, making their way onto beaches in perfect sync with tides and lunar cycles.
What happens during a Grunion Run?
As waves wash up the beach, females ride them in and burrow tail-first into the wet sand, where they lay between 1,600 and 3,600 eggs in a single spawning event.
Males then curl around the females and release milt to fertilize the eggs before quickly returning to the ocean with the next wave. The entire process can last less than a minute, although some fish may remain briefly stranded on the sand before retreating.
Once buried, the eggs stay protected in the sand for about 10 days, incubating until the next high tide series triggers hatching and carries the larvae back into the sea. The spawn season typically runs from March through August.
When and where to see it
This 2026, grunion runs are expected to continue through mid-to-late April, with the next visible events taking place on April 17, 18, 19, and 20, typically during a two-hour window between roughly 9:45 PM and 1:50 AM, depending on the day and location.
These times are based on predictions for Cabrillo Beach and may shift slightly along the coast (arriving a few minutes earlier in San Diego and a bit later in Santa Barbara).
The phenomenon can also be observed on many sandy beaches across the region, especially:
- Huntington Beach.
- Newport Beach.
- Santa Monica Beach.
- La Jolla.
How to observe responsibly
Although the Grunion Run is a rare and striking natural event, it is also a delicate one. The California Department of Fish and Wildlife advises visitors to observe quietly and avoid interfering with spawning activity. To minimize impact, it is recommended to follow these guidelines:
- Check local beach rules or curfews before visiting.
- Do not touch or handle fish.
- Avoid stepping on wet sand where eggs may be buried.
- Use a red-filtered flashlight to reduce disturbance.
- Keep noise levels low and stay at a respectful distance.
