You can switch between Jason and Lucia in GTA 6, but not at every moment. Rob Nelson of Rockstar North explained the rules to Famitsu: the story decides when you are free to choose, when a mission locks you to one lead and when the game swaps you itself. This guide covers each case.
Free switching
In missions that allow it, and outside missions, you can take control of either character, or bring the two together. When you are not playing one of them, that character carries on with their own schedule around the safehouse. No button, cooldown or switch menu has been described, so the controls will be added once the game is out.
Missions that lock you to one lead
Story progress can restrict switching. Where Rockstar wants one character's perspective, as it did in GTA V, the switch is locked. Nelson gave an example: an early mission through a high-rise housing estate could be freely switched during development, and Rockstar fixed it to Jason. Nelson describes Jason as former special forces when he explains why. Rockstar's own profile says only that Jason served in the Army, so treat the special-forces detail as one interview line. There is no published list of locked missions.
Forced swaps during a mission
Some missions swap you at set points. In the demo chase after a bank robbery you start as Jason, shooting at pursuing police from a car that Lucia drives. The mission then switches so that you drive as Lucia while Jason and Raul shoot from the back seat. Nelson calls Lucia's driving skill excellent. Edge also reports that during a getaway with both leads you can switch control between driver and passenger.
Sharing a car and doing jobs together
You can play Lucia in the passenger seat checking her phone while Jason drives, as Dazed also reports. Robberies work the same way. The convenience-store robbery in the demo is a set mission or a free-roam activity, and you can do it alone or ask Lucia to join. How her presence changes the job has not been described. The money guide lists the other robberies.
Relationship status and the bond
Nelson says whether Jason and Lucia act as a couple or as partners in crime is up to the player, and most situations are built so the two must cooperate either way. A relationship status is shown in game next to your bank balance. If you do not invest in the relationship, options such as holding hands or kissing are lost, and effort can win them back. Edge reports the bond has four levels, built through shared activities, and that Nelson declined to confirm whether marriage is possible.
Is there co-op?
No. Rockstar calls GTA 6 a single player experience, and PlayStation lists it as one player with offline play enabled. A second character controlled by the game is not a second human player. For the wider online picture, see multiplayer and online.
What is not announced yet
The exact controls for switching and the full list of locked missions have not been announced. After launch, this page will add a mission-by-mission list showing which story missions lock you to Jason or Lucia, linked from the walkthrough.
For each lead's background, read the Jason Duval and Lucia Caminos profiles, or browse the characters hub.