How much difference is there between a hot tub and a swim spa?

They share warm water and little else. Here is how the two differ in purpose, size, and cost.

September 4, 2026 · 3 min read · Updated September 7, 2026

Two different purposes

A hot tub is built for warm relaxation and hydrotherapy in a compact footprint. A swim spa adds a strong current for exercise, turning the water into a place to train as well as unwind. Related: How difficult is it to maintain water quality in a swim spa?

The overlap is only the warm water. In purpose, size, and daily use, they are quite different machines that happen to share a family resemblance.

Keep reading: Which shell material lasts longest in a premium outdoor hot tub?, What does energy efficient insulation really mean for a luxury spa?, How difficult is it to maintain water quality in a swim spa?. See how Spaholm helps you a considered guide to luxury hot tubs and swim spas.

Size and space

A hot tub fits comfortably on many terraces and decks, while a swim spa is considerably larger and heavier, closer in footprint to a small pool.

That size difference shapes everything downstream, from the foundation to the running cost. A swim spa is a bigger commitment of space and structure. Related: What does energy efficient insulation really mean for a luxury spa?

How you use them

A hot tub invites you to soak, ease tension, and socialize in warm water. A swim spa lets you swim against a current, exercise, and then relax, often with adjustable temperature zones. Related: Can a swim spa deliver a genuine workout for serious swimmers?

If your goal is pure relaxation, a hot tub may be all you need. If you want year round exercise in a smaller footprint than a pool, a swim spa earns its size. Related: When does a swim spa make more sense than a full pool?

Cost and commitment

A swim spa generally costs more to buy, install, and run than a hot tub, reflecting its size and capability. The budget bands sit higher across the board.

Choosing between them starts with purpose. Name what you want the water to do, and the right machine, and the right cost, follow from there.

Key takeaways

A hot tub is for relaxation, a swim spa adds exercise
Swim spas are much larger and heavier, near a small pool
Size drives foundation, space, and running cost
Start from purpose, then the right machine follows

Written by

Julien Jimenez

Julien Jimenez is an independent software builder based in Paris. He designs, ships, and operates focused SaaS products for small businesses and independent professionals. Read the full author page.

Frequently asked questions

Can a swim spa also be used like a hot tub?

Yes. Many swim spas offer a warm relaxation zone alongside the swim area, so they serve both purposes. That versatility is part of why they cost and weigh more.

Which is cheaper to run?

Generally the hot tub, because it is smaller and holds less water to heat. A swim spa's larger volume and capability place its running costs higher.