None! You don't need any. Just download offline maps
The location is interior from the nearest town, tucked between hills. I would say almost no reception.
No reception
None
There is weak WiFi at the visitor center. No cel.
Since i went there to get away, reception was not something that was important at the time. The park is in a relatively undeveloped, rural part of coast South of Half Moon Bay... And in a steep canyon/valley. Now that i think about it, we did not have reception until we were several miles back toward the coast highway. I would therefore recommend it as a place to take the kids to force them off their phones and back into the real world.
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