I will paste a copy below of Manhattan Beach website with all information. https://www.citymb.info/visitors/parks-and-facilities Also, the city of Hermosa beach opens at 6AM. Here is the link to the city page with all information. https://www.hermosabeach.gov/enjoying-hermosa/beach-strand-and-pier-regulations
It varies. During the summer a couple towers will open at 9 am. One guard will be in a truck in Manhattan as early as 7. Most every tower will be open by 12 noon.
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