When Does Fantasy Baseball Start and End?

Fantasy baseball is among the most storied traditions in fantasy sports, and it’s a great way to get more invested in the MLB season. If you’re ready to get started with fantasy baseball, it’s important to know the key dates in the season, including when it starts and ends.

When Does Fantasy Baseball Start?

Most fantasy baseball leagues begin running at the start of the baseball season and run for the duration of the regular season. Because of the addition of international series games in recent seasons this means the league often begins around mid-March. Opening day for the 2025 MLB season was March 18, when the defending World Series Champion Los Angeles Dodgers started their defense with a 4-1 victory over the Chicago Cubs and a 6-3 win the next day.

While the majority of leagues begin with opening day, if you missed out this year but still wanted to get in on the action you can start a league today. One benefit of so many games in a baseball season is it means there’s still plenty of action to play with even for a mid-season start.

Does It Matter if a League is Head-to-Head or Rotisserie?

Most fantasy leagues use two primary styles: head-to-head and rotisserie. Head-to-head leagues usually work on a weekly basis, with teams facing off against each other either directly scoring points based on stats or competing in a series of categories, like hits, home runs, ERA, and others, with the goal of winning the most categories. Leagues using this format traditionally have a regular season and playoffs, with the latter occurring in the final weeks of the MLB regular season.

In rotisserie leagues teams accumulate points all year long and everyone competes against everyone to accrue the most points. This type of league does not require playoffs, changing how the end of the year plays out, but there is no difference to the start date in most cases.

When Do Fantasy Baseball Playoffs Start?

When playing in a fantasy league with playoffs it is customary to use the final weeks of the real world regular season for the playoffs. The exact number of weeks required for your playoffs will vary based on the number of teams and the number of weeks assigned to each match-up.

The most common format for fantasy baseball playoffs is to use a three-week structure. Under this format, the fantasy baseball playoffs start on Monday, September 8 and run for the final three weeks of the MLB regular season.

When Is Fantasy Baseball Championship Week?

Leagues using a playoff format, or leagues following a traditional baseball approach with a single championship game for the top two performing teams, may hold a championship week on the final week of the MLB season. For the 2025 MLB season this is the week of games running from Monday, September 22 to Sunday, September 28. 

Can You Play Fantasy During the MLB Playoffs?

Most commonly fantasy sports leagues only run during the regular season. This is primarily due to the logistical problems that come with the rapidly dwindling number of teams making it hard to host rosters for multiple fantasy teams. That doesn’t mean there are no fantasy option come MLB playoffs however. You may consider trying:

• Daily Fantasy: A popular option during the regular season as well, in daily fantasy games you pick a roster of players, usually using a set budget to buy players with set player values, and compete against other managers. You can jump into large public leagues or create a smaller one to compete against your friends while the playoffs go by.
• Playoff Rotisserie: One area where the popularity of non head-to-head formats benefits fantasy baseball is the playoffs, where rotisserie can be an excellent option to keep playing when the MLB playoffs start. Whether you draft players or use a “buy with a budget” approach, playoff fantasy with rotisserie scoring lets you consider not just a player’s talent but also his team and the number of games he’s likely to give you.

Fantasy baseball is a great way to enjoy the game you love to an even higher level and to have fun with your friends. With the official start date of the MLB season and fantasy baseball season come and gone the best time to start your league if you haven’t already is now. The sooner you get up and running the more time you’ll have to compete with your friends before the season ends!