Polearm OA clarification

[Provo]

I frequently see talk of sentinel and polearms as a powerful combo. The obvious reason being that you can stop a baddie before they reach you.

However, by my reading, the rules state that you receive an OA only when an enemy LEAVES your threatened area. Not when they enter or move through your area (unless you have UA's tunnel fighter feat)

Am I missing something? Has this been addressed in errata? Obviously it would make sense for polearms to allow you to attack an approaching target, but do the rules agree?

[uraniumrooster]

I frequently see talk of sentinel and polearms as a powerful combo. The obvious reason being that you can stop a baddie before they reach you.

However, by my reading, the rules state that you receive an OA only when an enemy LEAVES your threatened area. Not when they enter or move through your area (unless you have UA's tunnel fighter feat)

Am I missing something? Has this been addressed in errata? Obviously it would make sense for polearms to allow you to attack an approaching target, but do the rules agree?

The Polearm Master feat allows you to make an OA when an enemy enters your reach, as long as you're using a Glaive, Halberd, Pike or Quarterstaff.

[Provo]

Thank you! I have somehow been skipping over that aspect of the feat

[NNescio]

I frequently see talk of sentinel and polearms as a powerful combo. The obvious reason being that you can stop a baddie before they reach you.

However, by my reading, the rules state that you receive an OA only when an enemy LEAVES your threatened area. Not when they enter or move through your area (unless you have UA's tunnel fighter feat)

Am I missing something? Has this been addressed in errata? Obviously it would make sense for polearms to allow you to attack an approaching target, but do the rules agree?

Also, the UA Tunnel Fighter fighting style grants a reaction attack ("reaction to make a melee attack") against a creature which moves more than 5 ft while within your reach if you took the bonus action to assume the defensive stance, which is not the same as an opportunity attack. As such, this will not trigger Sentinel's "drop target's move to 0" feature, and it will also actually eat up your reaction to perform (since it's not an OA, it doesn't work with Tunnel Fighter's defensive stance's main benefit).

[Yuion007]

This is one of my favorite combos as a barbarian. The extra attack with the butt end does a min of 8 dmg with the barb dmg addition. And it can keep pesky disengage spellcasters from getting away.