The 2026-27 NBA season officially begins on October 20, but the return to basketball happens in stages. For fans, the most useful sequence is straightforward: training camps open on September 29, the preseason begins on October 3, Opening Day rosters are set on October 19, and the regular season starts on October 20. Those milestones are close together, but each serves a different purpose.
NBA 2026-27 timeline before the regular season
| Date | Milestone | What it means |
|---|---|---|
| Sept. 29 | Training camps | League-wide camp opening for preparation, practices and roster evaluation. |
| Oct. 3 | Preseason begins | Exhibition games start; they do not count toward the regular-season standings. |
| Oct. 19 | Opening Day rosters | Teams must have their rosters set for opening day by 5 p.m. ET. |
| Oct. 20 | Regular season begins | Games begin counting officially toward the 2026-27 standings. |
September 29: training camps officially open
September 29 is the league-wide milestone for NBA training camps to open. It marks the move into collective preparation before preseason games. Coaching staffs use this period to install systems, test lineups, evaluate conditioning and begin defining roles and rotations.
There is an important nuance: September 29 is not necessarily the first day every player may report to a team facility. The official calendar lists September 21 as the first allowable reporting date for players on teams participating in preseason games outside North America; those teams may open camp on September 22. For all other veteran players, the first allowable reporting date is September 28. In other words, September 29 is the general opening of NBA training camps even though some groups can begin earlier.
October 3: preseason games begin
Four days after the league-wide camp opening, the NBA preseason begins on October 3. The NBA G League's official key-dates page lists the NBA preseason as running from October 3 through October 16. This is the first chance to see teams play opponents, but the games are still part of the preparation phase.
For fans, the best way to read preseason games is to look for trends without treating them as final. Minutes can be managed, starters may rest and players competing for roster spots often receive larger opportunities. The final score does not enter the regular-season standings.
October 19: Opening Day rosters are set
On October 19, by 5 p.m. Eastern Time, teams must have their rosters set for Opening Day. This is the point on the calendar when much of the evaluation from camp and preseason turns into concrete decisions about who begins the year with the team.
The name of the milestone matters: it is the roster for the start of the season. It should not be read as a list that can never change over the rest of the year; later transactions can still occur under applicable league rules and windows. For cuts, signings and last-minute changes, the days immediately before October 19 are especially important to watch.
October 20: the regular season begins
The day after the roster deadline, the 2026-27 regular season begins. The NBA lists three games for October 20: Boston Celtics vs. Detroit Pistons at 3 p.m. ET, Philadelphia 76ers vs. New York Knicks at 7 p.m. ET, and Oklahoma City Thunder vs. San Antonio Spurs at 9:30 p.m. ET.
From that point forward, results count in the standings. Rotations also carry a different weight: teams can still experiment during the season, but every game now has a real competitive impact.
How to read the sequence without mixing up the milestones
- Training camp is not the preseason: camp is the practice and evaluation period; preseason is the schedule of exhibition games.
- Preseason is not the regular season: those games are for preparation and do not count in the official standings.
- October 19 rosters are the opening-day cutoff: the deadline organizes who starts the season with each team.
- October 20 is the competitive switch: from opening night onward, results count toward 2026-27.
The calendar in one sentence
To follow the NBA's return without getting lost, think of a progression from preparation to competition: camp opens on September 29, teams move into preseason games on October 3, Opening Day rosters are set on October 19, and the regular season begins on October 20.
Official sources: NBA — Key dates for 2026-27 season and NBA G League — Key Dates.
