Why do seagulls fly around the beach areas?

because there is lots of food on the ocean by people who just litter or forget to clean up spills of drink or food or crumbs

Seagulls are opportunistic scavengers.

https://en.wikipedia.org/wiki/Seagulls

Gulls are seabirds and the beach is a natural environment for them. It's the ploughed fields and rubbish dumps that aren't natural, but many species of gull are opportunists and will go where the food is. Black-headed, common and herring gulls spend a lot of time away from the coast. Kittiwakes and little gulls don't. A beach that hasn't been cleaned-up for the tourists provides plenty of gull food in terms of washed-up shellfish and other dead animals, as well as incautious ragworms. Gulls also catch small fish. A sandy or muddy beach may look barren, but you'd be amazed at how much stuff does live there.

Its always interesting to see a lone gull far from the ocean.

Feeding patterns.

You will notice many "sea gulls" inland. Especially near garbage dumps.

Again, it is about filling the belly.

They aren't just in beach areas, the California Gull aka Sea Gull aka Sea Vulture is the state bird of Utah.

http://www.infoplease.com/ipa/A0108279.html