Cockroaches often enter bathrooms through shower drains, attracted by warmth, moisture, and darkness. Even with regular cleaning, they can still crawl up the pipes — but a simple balloon can block their path.
To try the trick, remove the shower drain cover, cut the ends off a regular balloon to create a short tube, and stretch it over the drain opening before replacing the cover. Water can still pass through, but the tight seal prevents roaches from squeezing up the pipe. Replace the balloon occasionally to keep it effective.
Along with this barrier method, reduce moisture, wipe surfaces dry, seal cracks around pipes, and keep the bathroom clean. Roaches thrive in damp, hidden areas, so prevention is a mix of cleanliness, maintenance, and smart blocking techniques.