A Wizard PC Teleports their party from a safe place directly to the location of a group of foes, who the party intends to attack.

If the foes did not know this was about to happen, they should be surprised.

How does initiative work in this situation - does the Teleport take place on the Wizard's first turn in combat, or prior to combat entirely? To illustrate why I am confused, there are a few possible adjudications below.

1. The moment the Wizard decides they want to Teleport into combat, initiative is rolled. The Wizard casts Teleport on their turn, which may be after the turns of their companions, and teleports to the foes' location. Any foes who rolled higher initiative will no longer be surprised. The Wizard takes their next turn in the second round, in which no foes will be surprised.


2. At the point the Wizard casts Teleport, they are not in combat. After the spell is cast, (since the party intends to immediately attack) the combat begins, and initative is rolled. The Wizard takes their next turn in the first round, while some foes may still be surprised (depending on their initiative).


3. Case #1, but the Wizard can use Ready-ing the Teleport spell to effectively turn it into case #2.

I think you are confused about how surprise works:

The GM determines who might be surprised. If neither side tries to be stealthy, they automatically notice each other. Otherwise, the GM compares the Dexterity (Stealth) checks of anyone hiding with the passive Wisdom (Perception) score of each creature on the opposing side. Any character or monster that doesn’t notice a threat is surprised at the start of the encounter.

If you’re surprised, you can’t move or take an action on your first turn of the combat, and you can’t take a reaction until that turn ends. A member of a group can be surprised even if the other members aren’t.

The GM decides who is surprised, not the initiative roll.

So here is how that event would play out.

1. Wizard teleports into combat


2. Everyone rolls initiative


3. Turns start in initiative order


4. Everyone who is not surprised gets to act while people who are surprised skip their turn


5. Assuming the PCs have not teleported again before the end of round 1, round 2 of combat would start


6. Turns begin to take place in initiative order; no one is surprised anymore

For scenario 3:

The wizard cannot ready an action outside of combat, so he could not ready the teleport spell until combat has begun.

Initiative starts after the wizard teleports in, but that's not the whole story.

This is fundamentally no different from someone arriving in combat by any other means. Initiative represents how quickly they all react to a threat, so it only starts when there's a threat present. So ignoring surprise, the outcome is that the wizard would arrive, then everyone who rolled above him would act, then the wizard, followed by everyone else.

But you can't ignore surprise.

Compare this to a case that's almost identical from the perspective of everyone else in the fight: instead of teleporting in, the wizard was invisible and hiding among them. This is the textbook case for surprise. If nobody noticed him lurking there then the enemies will all be surprised. And they can't notice him in advance if he teleports in, because he's not there.

Now the turn order is that the wizard teleports in, then gets a turn, then everyone who rolled above the wizard gets a turn, then the wizard gets a second turn, and then everyone who rolled below the wizard gets a turn. Okay, fine, battlefield teleportation is really powerful.

However, this is very sensitive to exactly how the DM wants teleportation to work. The above case assumes it's like Nightcrawler from X-Men: BAMF, ninja in your face. Tweak it a little so that it's like a Star Trek transporter, where your arrival is announced by a few seconds of swirly lights and noise, and now nobody is surprised. They all get to react to the wizard's arrival normally.

If you don't like the extreme result of everyone being surprised, but still want some benefit for setting up a teleport ambush, consider giving the wizard advantage on initiative. This makes this tactic powerful (especially if they choose their destination carefully) without being a guaranteed first strike.

In general, Combat starts as soon as an attacker has a target. When Teleport is cast, no one on either side knows where the others are, so no one has a target. (If you somehow know where the enemies exact position is before the teleport, say with binoculars while overlooking the enemy, then you are in a surprise round with everyone but the caster readying an action to attack their target once the teleport is resolved.)

After the teleport, everyone has to acquire a target. If you teleported into the open, combat starts and no one is surprised (everyone notices everyone at the same time). If you teleport into an empty tent or very dark corner however, the party can attempt a stealth check to begin their attack with surprise (The party notices them, but the enemy still needs to notice the party).

Note that in any way this plays out, effectively the teleporter casts on turn 1, which will play out as a normal round like the party where performing an ambush by foot. (The Teleport just makes it easier to close the distance without being noticed)

I also want to note that no matter how the DM rules on this first round, as long as the party planned the ambush right (during meal time or night watch); that the enemy will also have to spend time getting their armour/weapons or fight without them. So the best benefit here is catching the enemy with their pants down rather than by surprise.

The Teleport spell happens before initiative is rolled

You don't know whether combat is going to occur until the effects of the Teleport spell are resolved. Unless there is a permanent teleportation circle at the ambush location or they have an 'associated object' from where they want to teleport to, there is a chance that the players will land 'Off Target' or in a 'Similar Area' rather than the intended location (Teleport spell, PHB pg 281). As a DM, you'll have to consider how well they know the area they are trying to teleport to in order to determine their chances of teleporting to the correct location.

The players can be prepared to fight right after teleporting and I would reward them for the tactic by having the enemy be surprised.