The National Sluggers League, NSL, is an 8-man Mario Super Sluggers league in the central United States. The season runs throughout March. Each year, a series of offseason events take place. Jacob is the reigning champion after the 2026 season. Andrew and Joe are each two-time league champions. Andrew also won the first Mario Sluggers Online Tournament. The National Sluggers League takes pride in being the loudest, hypest, and best Mario Sluggers League on the Internet. 

The National Sluggers League ran its 5th season during March 2026. Joe won the Day Division and was the top seed in the playoffs. Jack won the Night Division. In the championship game, Jacob beat Jack 2-0 to win his first NSL Championship.

The NSL tried something new in the month of June with the NSL Stars Tournament. This tournament had two twists on the usual NSL event. We used stars for the first time since the 2023 winter event, as a testing ground for possible implementation for 2027. Additionally, games were uploaded one by one instead of one long livestream. Joe was the champion of the double elimination bracket.

On July 3rd, the NSL held its third annual Summer Showdown. This tournament featured the same format and competitors as the Stars tournament. Joe took home the crown, marking back-to-back offseason event wins, back-to-back Summer Showdown wins, and four straight solo offseason event wins.

The fifth annual Fall Classic is coming this autumn. The date has not been planned, and the format will be decided once attendance of the event is known. The last three offseason events have been only Day Division members playing, but Jack has declared his intention to participate in the Fall Classic. The event will be played with stars on, as the final testing ground for the potential change in 2027. As always, the event could also be used as a Play-In Tournament if necessary.