In everyday French, partir à is commonly used for going to a destination.
You may also hear partir pour in some contexts, but partir à la plage is very natural and common.
Also, à la plage is the normal way to say to the beach or at the beach, depending on context.
It can describe either, depending on context.
It might mean:
or
French present tense is flexible like that.
A simple pronunciation guide is:
Zhuh meh lay boo-tay d-oh dahn lah gla-see-air ah-vahn duh par-teer ah lah plazh
A few helpful points:
The word order is very standard in French:
So the structure is basically:
Subject + verb + object + place + time/context
This is one reason the sentence is a good model for everyday French.