Is Kailua Bay safe to swim?

As of July 19, 2026, Kailua Bay in Hawaii County, Hawaii is clear to swim. Blue-green algae are not currently monitored at this water. No fecal-bacteria advisory is posted (state beach program). Rainfall over the past week totaled 0.5 in, which can wash bacteria and nutrients into the water.

How this read is built

Kailua Bay is a lake in Hawaii County, Hawaii. Blue-green algae are not currently monitored at this water.

Blue-green algae (cyanobacteria) blooms are most common from midsummer into early fall, when the water is warm, calm, and rich in nutrients from runoff. They can produce toxins that make people sick and can be rapidly fatal to dogs, so skip water that looks green, scummy, or like spilled paint, and keep children and pets out of it.

Is it safe to swim in Kailua Bay right now?

Kailua Bay is clear to swim today. Blue-green algae are not currently monitored at this water. Conditions can change quickly with wind, heat, and rain, so check the posted signs and look at the water before you get in.

Does Kailua Bay have blue-green algae (cyanobacteria)?

Blue-green algae are not currently monitored at Kailua Bay. Watch for green, blue-green, or paint-like scum and avoid the water if you see it.

Can dogs swim in Kailua Bay?

No bloom is detected at Kailua Bay today, but dogs are much more vulnerable to blue-green algae than people, and blooms can form within hours. Always keep dogs away from water that looks green, scummy, or discolored, and rinse them off after swimming.

How many Hawaii lakes and beaches have swim advisories today?

Today, 0 Hawaii waters are under a swim advisory and 106 more warrant caution, out of 402 monitored waters SwimZone tracks in the state.

How is Kailua Bay's water quality measured?

SwimZone builds this read from EPA CyAN satellite imagery for blue-green algae, official beach and fecal-bacteria advisories where a program monitors Kailua Bay, and a recent-rainfall overlay, all refreshed daily. It was last updated July 19, 2026.