When rolling a 20 for a Death Saving Throw, can you move and take Actions that turn?

Question

My intrepid adventuring character has been attacked, and the damage reduced him to 0 hit points and falls unconscious. On his next turn, he rolls a Death Saving Throw, and gets everybody's favorite die roll: a natural 20! He regains 1 hit point, and thus regains consciousness.

Now that he's conscious, can he still move and take an action for his turn? The rules say that you roll a Death Saving Throw "Whenever you start your turn with 0 hit points," but it's not clear to me if that's replacing one's normal turn, or if it's just at the start of one's turn, and the only reason one normally doesn't follow it with a movement and action is because unconscious creatures are incapacitated and can't move.

There's some discussion in the comments of an answer to "Do you regain consciousness immediately on a 20?", but it doesn't seem to have an authoritative referenced resolution to the discussion, and it seems that if it's worth talking about in comments it's worth asking as a full-fledged question.

Answer 1

The entry for Death Saving Throw says:

Whenever you start your turn with 0 hit points....

So this just means that you make the throw at the beginning of your turn. However, nowhere in the description does it say that it requires any kind of action to make the save.

A saving throw is an instant response to a harmful effect and is almost never done by choice.

There is no general rule saying that doing any kind of saving throw (of which a death saving throw is one) takes any kind of action at all. Indeed the quote above would imply that it is not one. This especially makes sense since many saving throws are made not on your turn and thus would be unlikely to use your action or movement or reaction. Additionally, if saving throws did take any kind of action to resolve, it would be quite a huge power boost for those abilities that cause them.

That being the case, once you regain consciousness, you should have all of your move and action available to you to use as you see fit.

A good point from @MivaScott:

Most unconscious people are also prone. So while they are now conscious, I would still apply the "prone" condition for that turn (half movement length for crawling, get attacked with advantage, etc).

Answer 2

I think, RAW, you are allowed to take a turn when you roll a 20 on a death saving throw. Death saving throws are specified to be saving throws which you make at the start of your turn (PHB 197), and saving throws are not actions (They aren't listed in any of the actions you can take in the PHB and don't have an action cost listed in their section on PHB 179).

When you fall to 0 hit points and do not die of massive damage, you fall unconscious, which ends if you regain any hit points (PHB 197). Since you regain 1 hit point upon rolling a 20 on the death saving throw, your unconscious state would end without using any actions on your turn, and you would therefore have your full turn available to you.

This is just my reading of it; to me, it would make sense for DMs to rule that the player must spend some time (read: actions) to recover from being unconscious/close to death. Do note that a PC would be prone after waking up, so they'd have to spend half their speed to stand up if they wanted to.

Answer 3

If you succeed your death saving throws by rolling successfully three times in a row, your character has become stable (ie, 0 HP). Stable characters are still unconscious, and so cannot take any actions. If you save vs. death and roll a natural 20, you regain 1 HP and so are able to take action as you are now conscious.

From the Player's Basic Rules

DEATH SAVING THROWS

On your third success, you become stable (see below).

Rolling 1 or 20. If you roll a 20 on the d20, you regain 1 hit point.

STABILIZING A CREATURE

A stable creature doesn’t make death saving throws, even though it has 0 hit points, but it does remain unconscious... A stable creature that isn’t healed regains 1 hit point after 1d4 hours.

Answer 4

In my opinion, you shouldn't be able to take actions/movement. A lot of times after a real life KO (such as witnessed in boxing, ufc, etc.) the person regaining consciousness is often told not to move around too much right after waking up, because they might still be physically rattled and not able to keep their balance/feet under them. Maybe make a CON or DEX roll to see if they are physically able to perform on their turn? Maybe force them to act from prone for a round or two? Even an irl barbarian like Mike Tyson has been too wobbled for the ref to let him keep going after a vicious knock down. It has nothing to do with willingness, I am sure there are a few people would want to keep going after a KO, but their bodies just aren't responding correctly immediately after a KO.