Seagulls aren't there to ruin your beach experience, but it sometimes seems that way. Seagulls are searching for litter and garbage to eat. The best way to repel them is to keep the beach clean and free of trash. In addition to that, there are several temporary solutions to keep seagulls away without hurting them.
Choose the lowest point of the beach on which to spread your blanket. Seagulls prefer to sit on the highest point of an area to roost.
Set a campfire on the beach. The smoke from the fire will repel the seagulls. Don't cook food on the campfire; the smell will only attract more seagulls. (Check that your beach allows fires.)
Clear the area of all garbage and food. Throw trash in garbage cans located far from where you're sitting. Seagulls fly to the beach in search of food.
Light small fireworks. The sound of the fireworks will scare the seagulls. Check local ordinances for the legality of lighting fireworks at your beach. If fireworks aren't allowed, strike two metal objects together. The clanging sound will scare the seagulls.
Blow a whistle in short, loud bursts. Run toward the seagulls while blowing the whistle. You'll look as if you're a large predator and will be seen as a threat. The seagulls will fly away.
Place seagull spikes around the area in which you're sitting. Seagull spikes are nonlethal; seagulls just don't like sitting in-between them.
Studies have shown that ultrasonic devices don't work on birds. Don't purchase one if you're trying to rid the beach of seagulls. If you're really serious about keeping seagulls away, sprinkle one tbsp of Ornitrol powder over one cob of corn. Place the corn cob on the beach. Ornitrol controls the reproduction cycles of seagulls for three to six months. It will decrease the number of seagulls born in the area.