Nintendo Confirmed on their product page For the upcoming Mario Kart 8 Deluxe Booster Course Pass, new tracks can be streamed online even if you don’t have a Booster Course Pass. Beginning March 22, you will be able to participate in global and regional competitions online. This means that the new tracks won’t cause any fragmentation of the online Mario Kart 8 Deluxe user base, as all players will have access to them. However, if you want to race through the new tracks in both single-player and multiplayer, you’ll obviously need to own the Mario Kart 8 Deluxe Booster Course Pass, which is available for free with the Nintendo Switch Online+ expansion pack, or purchased separately. The Mario Kart 8 Deluxe Booster Course Pass will be delivered in batches, with 8 courses releasing in 6 waves ending in 2023. This gives players 48 new courses to play in single player, multiplayer and online multiplayer starting March 18th.
“Mario Kart 8 Deluxe – Courses from Wave 1 of the Booster Course Pass can be played locally or online with friends and competitors starting March 18, even if only one player owns the Booster Course Pass or accesses it as part of Nintendo Switch Online + Expansion Pack Membership. From March 22nd, Wave 1’s lessons will also appear in a random selection when anyone plays a global or regional match online. “