How do I stop new users from entering a running journey while current users finish it?

Use When entry closes in the Audience-based entry element. It's available only when Entry schedule is One-time entry and Define who enters the journey is Existing and new users or Only new users.

• Never (default): new matching users keep entering for as long as the journey runs.
• On a specific day: after the date and time you set, no new users enter. Users already in the journey continue: waits, sends, and branches keep working.

Things to know:

• With Subscriber's device timezone, entry closes at the set time in each subscriber's local timezone, so it closes in waves over up to 24 hours.
• Use the same timezone option for entry start and entry close. Otherwise the journey may not launch, with End entry must be later than start entry or End entry is not later than start entry in timezones: ….
• The close date field is locked while the journey is running. To change it, pause the journey, set the new date, and click Resume campaign.
• After entry closes, the campaign status shows Active · entry closed, or Active · entry closed · N in flight while N users are still moving through the journey.

Learn more: When entry closes