There are several hot springs / hot ponds in the Puna district on the east coast of the Big Island. Most are publicly accessible and especially if you are staying more than 7 days on the Big Island, these make a great addition to your itinerary!
Have you ever wondered what it would be like to sit in a warm pool that is heated by volcanic energy? From personal experience I can tell you that it is pretty great, especially if you realize what makes the water warm!
Why are Hot Springs hot?
It rains a lot on the windward (East) side of the Big Island, up to 300 inches (10 meter) per year. Most of this water does not flow directly to the ocean but sinks down into the ground until it hits a barrier. On the Big Island this barrier is made out of salt water which is more heavy than fresh water. The water in this layer then slowly dissipates to the edge of the island and flows into the ocean.
In the volcanic area’s on the Big Island, the water flows through rocks that are heated by magma. This heat is absorbed by the water and taken along to the coast. As the water moves away from the magma it cools down a bit (especially if cold water mixes in), but the water stays warm enough to give the visitors of the Big Island a comfortable warm bath!
Hot Springs on the Big Island
Warm springs are commonly found along the Puna coast from Cape Kumukahi to `Opihikao. The two most popular and accessible hot ponds are:
Ahalanui Hot Pond
Ahalanui park is a park build around the Ahalanui Hot Pond. There is a picnic area, showers and toilet facilities. It is a popular destination for locals, and especially in the weekends the place gets crowded. It is best to stay away in the weekends and visit early in the morning (before 9 a.m.) to avoid the crowds.
Pohoiki Warm Spring
The Pohoiki warm springs are part of the Isaac Hale Beach Park in Puna. To find the biggest pond (which is actually a collapsed lava tube), locate the boat ramp, and from there follow the coastline for about two minutes. You should see the hot pond on your right about 80 yards inland.
Hygiene issues for Big Island Hot Ponds (?)
There are some hygiene concerns about the hot ponds on Hawaii. It is not unusual that the bacterial count in the hot ponds exceeds the EPA and state guidelines (source). This is mostly caused by the combination of poor sanitation in the area and large visitor numbers.
There are hundreds of people (including many tourists) using the ponds each day that are not affected, but as a tourist you are more vulnerable to the local bacterial population. The best way to stay safe when visiting the hot ponds is to use common sense:
- Never go in if you have a cut or infection
- Avoid crowds. Stay away in the weekends and go early in the morning when the ponds have been flushed overnight by tides.
- Take a shower after you get out of the water