Which One Should Be Used?
'On the beach' and 'at the beach' are both correct and can be used to refer to activities that are done in a certain location which in this case is 'beach.' There is a delicate difference between the two. 'In the beach' is the geographic location of a beach. 'On the beach' refers to the seashore.
On the Beach
'On the beach' is generally known as the equivalent to the seashore therefore when we use 'on the beach,' we are referring to activities and events that are done specifically on the beach itself. Have a look:
She was reading a book
Here, the subject is doing an activity that is done specifically on the seashore.
He loves sunbathing
At the Beach
'At the beach' refers to the geographic location of a beach. This can include the water, the seashore, etc. When we are referring to an action or event that is done in the location of the beach but we are uncertain about the exact spot, we can use 'at the beach.' For example:
The subject can be anywhere of this location but we are just aware of her whereabouts.
My son built sand castles
In the Beach
'In the beach' is incorrect and cannot be used under any circumstances. Use 'on the beach or 'at the beach' as instructed earlier in the lesson.
He plays volleyball
He spends most of his time
He watches the birds
at the beach.
Choosing the right preposition is tricky. While making this decision, one needs to consider the matter of euphony or the quality of being pleasing to the ear. The sentence at hand must sound natural to the audience and the correct preposition will help his natural flow.