After convenient pickup in Helsinki, head for the adventure center to suit up in a warm thermal snowsuit, balaclava, gloves, boots, and a helmet—way more gear than would fit in your suitcase. Once you're suited up and ready to face the Arctic elements, jump on a snowmobile (one vehicle per two adults) and head off in a convoy led by a guide who knows the area well.
Zip through the archipelago on a series of forest trails and around the frozen Gulf of Finland, stopping to get epic views and hear detailed commentary on life (human and animal) in the islands. Take a longer break on one remote island for a barbecue lunch over the campfire, prepared in the traditional Lappish way, and warm beverages to keep the cold at bay. Opt to explore further with a snowshoeing or ice fishing activity, then head back to the snowmobile center, and end your tour with drop-off in Helsinki.