You want to be comfortable in and around your hot tub. Without question, foam tiles are the most comfortable material to walk on underneath the hot tub. Their soft and comfortable fabric is easy and gentle to walk on but isn't always the best option depending on the ground surface.  A hot tub mat is another comfortable option that can be placed on solid and level ground, like concrete. It's affordable and protects from sharp objects, but it doesn't do so well when it comes to insulation or longevity. Remember, as much as carpet or foam sounds like the perfect base for your inflatable hot tub, they could be the worst, depending on the ground surface. For example, neither are great options for uneven ground.