Can I Dodge before a combat starts?

Question

My party is outside the open door to a room. We are pretty sure there are goblins in there, because we chased one this far, but we can't see them through the door so we suspect they are hiding inside somewhere.

When does initiative start for the imminent combat? In particular, can my dwarven fighter start Dodging and then walk into the room, ready for anything? Or do we need to go in and roll initiative first, potentially taking a bunch of hits before I can start Dodging due to my terrible initiative modifier?

I am a bit confused as to precisely when we should start taking combat rounds, in order to stay within the spirit of the rules. After all, I am pretty sure those goblins are waiting for me! I don't think they should be able to get the jump on me!

Likewise, what if we didn't know whether monsters were in the room? Could we just be overly cautious when entering new rooms, and prepare by Dodging before we head in?

Answer 1

The DM decides when rounds start, and usually this is at the beginning of actual combat. I don't see any particular reason you couldn't start dodging right away — and, in fact, telling the DM that you want to do this would usually start the beginning of combat rounds. (With the DM saying "okay then, roll initiative").

Dodge is described in the rules under "actions in combat". Previously, in the Adventuring chapter under "speed", it's noted that character and monster speed "assumes short bursts of energetic movement in the midst of a life-threatening situation". Although the combat chapter doesn't spell this out, I think it's completely reasonable to assume that the same applies: these are short-term high-adrenaline actions that you can't just keep up all that time. So you can't say "I'm always dodging unless I'm doing something else!" — that would completely exhaust even a high-level adventurer. The same chapter also explains that:

In combat and other fast-paced situations, the game relies on rounds, a 6-second span of time described in chapter 9 [the Combat chapter].

I added the emphasis — the important point is that while rounds are used in combat, that's not the only time they might apply.

So, indicating that you're ready to enter one of these high intensity bursts of compressed time represented by rounds is the normal way to go. In other words, to answer the title question you can dodge before combat starts, but doing so would start timekeeping in rounds.

You don't have to do it this way, though, and in fact, I think the normal approach would be to use the Ready action. This is technically also something you do in combat rounds, but in every D&D game I've seen, it's exactly what people do when they want to be prepared for something before combat has started per se. People arrange their readied actions, and possible out-of-rounds times happen, as other players set out what they're doing or where they're positioned (for a limit of a few minutes) until the first trigger occurs.

Here, you say "I'm going to ready to dodge when I see a creature on the other side of that door". This works out rationally, because Dodge requires you to be able to see the attacker to work, so there's really no point in having it "active" before that.

On the other hand, Dodge reflects a greater level of alertness all around (as modeled by advantage on Dex saves), and I think it's equally reasonable to say "I'm going to walk into that room on high alert — effectively, I'm taking the dodge action as I go in."

Either way, of course, prevents you from making an attack on your first round, even if there's obviously an enemy there to engage. That's the price of caution!

Answer 2

You can't dodge before combat starts, but if you're kicking down the door of a goblin barracks, the DM should declare that the combat started before you kicked down the door. Preparing to dodge and then kicking down the door was the PC's 'surprise round'.

Answer 3

Dodge and Ready are both defined in the Combat section, so presumably one cannot take the Dodge action or Ready an action until combat has begun.

That being said, this doesn't necessarily mean that you need to have rolled for initiative in order for combat to have begun; for example, surprise rounds are part of combat but take place prior to determining initiative*. In fact, the truth is any PC can initiate combat with any NPC at any moment they choose to do so; it just might not be a smart idea, and you may not always catch them by surprise. I think the most elegant way to handle this particular situation would have been to roll for initiative at the beginning of the chase (or if the chase occurred as the result of combat, to keep the previous combat initiative order).

*: See page 189 of the PHB. Under the Combat Step-by-Step sidebar it clearly indicates that surprise is determined prior to rolling for initiative, and in the text description of Surprise it explicitly states that surprised combatants cannot act during their first turn which effectively makes the first round the surprise round even if it is not explicitly called the surprise round by the text.