What two European groups, beside the Spanish, sent explorer to California coast?

The British and the Russians

Explanation:

The first Europeans to send explorers to the coast of California were the Spanish and the English. This exploration took place during the 16th and 18th centuries, however, no settlement was established, since until then both nations had no interest in establishing colonies in that region. Spain was more successful in this exploration, dominating the region in a marjoritary manner. In the 18th century, Russia joined explorers and beginnings to establish themselves exploratory in the same region.