Trinity Hot Springs

In the unincorporated community of Paradise, near Featherville in Elmore County, Trinity Hot Springs is a private membership club built around one large outdoor pool on Grouse Creek, just off the South Fork Boise River.

The pool is fed directly by the spring and kept untreated and chemical free, and the water behind it carries a distinction no other spring on this site can claim: Trinity Springs Water is certified by Institut Fresenius in Germany as a Natürliches Heilwasser, a natural health water, and the club and independent guides alike describe it as the only spring in North America holding that certification.

Read this part before you plan a trip: Trinity is not a walk in public pool. It is a members club, and at least one person in every party must hold a current Trinity Club annual membership before anyone can be on site or reserve anything. The good news is that membership is open to all, costs $35 a year per adult, and includes your first soak of the year.

Soaking runs in reserved 2 hour slots, lodging and camping are by advance reservation, and there is no online booking yet, so everything is arranged by phone or email. The club is open year round.

Soak Stats

The Soaking Experience

The pool is the whole show: one big outdoor pool with a gravel bottom, filled straight from the spring with no treatment and no chemicals, legally styled a Geothermal Therapeutic Soaking Spa in the club’s own materials. Per the club’s FAQ page, the water typically runs 95 to 108°F in summer and a milder 90 to 95°F in winter, varying with the season and the day, and the club posts current pool temperatures on its Facebook page.

Book a slot and the pool is yours for two hours, which keeps the water uncrowded in a way drop in pools rarely manage.

The water story goes further than the pool. The spring’s water was once bottled and sold internationally as Trinity Springs Water on the strength of the Fresenius certification, and the club still promotes it as drinkable: members may fill bottles and jugs at the source. Staying guests get the deepest version of the experience, with 24 hour pool access and quiet hours from 10 pm to 10 am. The one exception to the shared pool is Guenther’s Chalet, which has its own small geothermal hot tub on a private deck.

Location, Map & Directions

Trinity sits about 57 miles northeast of Mountain Home and roughly 100 miles, or 2 hours, from Boise. The standard route runs I-84 and US-20 east past Mountain Home toward Fairfield, then north on the Pine-Featherville Road through Pine to Featherville and Paradise. The road is paved with short gravel sections.

Two cautions from guide coverage of the drive: winter access can be snow limited beyond Featherville, and cell coverage is unreliable on the final stretch, so save your directions and the reservation number before you leave the valley. Featherville has limited services and Pine, about 9 to 10 miles west, a little more; Mountain Home is the last full services stop.

Place Information

Membership, Fees & Reservations

Membership comes first. Per the club’s membership page, general membership registration is open to all, with a signed membership agreement and liability waiver. Dues are $35 per year per adult (18 and older) and include the member’s first soak of the year plus a complimentary birthday soak. Be clear on what dues do not include: regular soaking beyond those two soaks is paid per slot, and at least one person in every party must be a current member for the party to be on site or to reserve lodging, camping or spa services.

Day soaking runs in reserved 2 hour slots at $15 per adult, $10 per youth (ages 5 to 17) and $5 per child (under 5), for members and member guests. Prepaid punch passes under the premium plans bring the per soak fee down to as low as $5, and the Paradise Club premium tier, at $55 per adult per month, includes unlimited soaking day passes and after hours pool reservations by advance approval. Member groups of 10 or more pay group rates from $10 per person down to $6 per person for groups of 50 plus.

Hours are the one thing this listing will not state as fact: the club’s FAQ, its membership terms and its Google listing currently publish three different sets of hours, so hours are marked not verified here and should be confirmed when you book. All rates on this page are the club’s published card, read in November 2026; the club notes that prices are subject to change at any time and are set by the reservation system’s quote at booking.

Facilities, Lodging & Nearby

The clubhouse anchors the property, with a lounge, a fitness studio and classroom, and a recreation and dining room. Around it are a private riverside beach (Wagon Town Park and Riverside Beach), picnic areas, the Source gift shop, changing rooms and showers, plus spa services and yoga and wellness programming. Retreats and events are a major part of the operation, with about 30 beds across 15 rooms and room for events of up to about 200 people. There is no Wi-Fi anywhere except Guenther’s Chalet, which is very much the point of the place.

Lodging

Nightly rates below are weeknight / weekend, from the club’s published card. Lodge Rooms 1 to 6 run $150 / $165. Cabin Rooms 9 and 10 run $270 / $290, and Cabin Suite 11 runs $280 / $300. Guenther’s Chalet runs $400 / $420, generally with a 2 night minimum; it is the top end of the property, with a full kitchen, a private deck, its own geothermal hot tub and the only Wi-Fi on site.

Every lodging guest is a member during their stay and gets 24 hour access to the pool, the bathrooms with showers and the changing rooms, with quiet hours from 10 pm to 10 am.

Camping

Membership is required to reserve camping, and campground guests get the same 24 hour pool access as lodging guests. The on site Paradise Campgrounds (amenities, no hookups yet) charge $30 per tent including 1 person, plus $20 per additional adult and $15 per additional youth. Car, RV and trailer camping runs $40 per vehicle including 1 person, with the same additional person rates. A second Riverside Campground across the road has no amenities.

Pets

Dogs are allowed by permission in the cabins, the chalet and the campgrounds for $20 per pet, up to 3 pets. They are not allowed in the lodge rooms or inside the fenced pool area, and they stay leashed everywhere else on the property.

History

People have been swimming in this pool for more than a century. The club’s own caretaker posting dates the pool’s history to 1912 and notes that generations of local families learned to swim in it, and the property appears as Paradise Hot Springs on USGS topographic mapping at least as early as the 1964 Featherville quadrangle. The Trinity name comes from the bottled water era, when Trinity Springs Water built an international following on the strength of the Fresenius Heilwasser certification; the bottled water has not been available for about a decade.

The modern chapter starts with a long closure. The Paradise Lodge and its pool were closed to the public for over 25 years before reopening in May 2016 as Trinity Hot Springs, run as a private community club on the historic property. A state water right permit for the Paradise Hot Springs source on Grouse Creek, covering heating use, was approved on March 2, 2016, matching the reopening; the permit file is on record with the Idaho Department of Water Resources. Older visitors also remember the place informally as the Paradise Plunge.

Safety & Health

The pool water is untreated spring water, which is the draw, and the usual hot water common sense applies: take breaks, stay hydrated, and think twice about long soaks for anyone with health concerns about hot water. The practical risks here are logistical. Membership and reservations have to be arranged by phone or email before you travel, cell coverage is unreliable on the last stretch of road, and winter conditions can limit access beyond Featherville, so arrive with your booking confirmed, your directions saved and a full tank from Mountain Home or Pine.

Best Time to Visit

Trinity works in every season, and the pool changes character with the calendar: warmest in summer, when it typically runs 95 to 108°F, and gentler in winter at 90 to 95°F, when a soak under falling snow is possible if the road cooperates. The club closes occasionally for maintenance, pool cleaning and private events in any season, which is one more reason every visit starts with a phone call. If you want the fullest version of the place, book a cabin or the chalet and use the 24 hour pool access that comes with it.

Nearby Hot Springs

Trinity anchors a strong South Fork Boise River corridor. Up the same river above Featherville, Skillern Hot Springs is a natural creekside soak, and the Forest Service pool at Baumgartner Hot Springs sits by its campground east of Featherville. Farther afield, the river pools at Sacajawea Hot Springs wait near Grandjean, and Atlanta Hot Springs serves the old mining town of Atlanta. More South-Central Idaho hot springs →