Foam grips (usually EVA foam) are a great choice if you prioritize comfort and a lightweight feel. They're soft on the hands, provide good insulation against cold poles, and are especially popular for touring and freeride skiing. One big advantage: foam works beautifully on poles with extended grip sections—those longer grip areas below the main handle that let you choke down on steep sidehills without adjusting your pole length.
The main trade-off is durability. Foam can compress over time and may show wear faster than rubber or cork, especially with heavy daily use. It also tends to absorb moisture, so your grips might feel damp after a sweaty tour.
If you're a backcountry skier or freerider who values comfort on long days and likes having an extended grip for varied terrain, foam is an excellent option. For resort-only skiers who want something that lasts season after season, rubber or cork might be the better long-term pick.