Invincibility frames are the period of time (measured in frames) during which a character cannot be attacked or damaged. Depending on which kind of invincibility the character has, the attack may "hit" or "miss".
A character with invincibility will be hit by attacks (so the attacker takes hitlag), but will not take damage or hitstun. This can be thought of as "blocking invincibility". For example, characters using a Starman have invincibility, as well as characters about to throw someone (this invincibility lasts 8 frames). Other examples of invincibility include:
- The 2 seconds (120 frames) after dismounting a revival platform.
- The secondary Ice Climber for a second when Belay is used.
- The start of Lucas' and Ness' PK Thunder 2.
- The entire duration of Squirtle's Withdraw (different from other examples, as instead of bright "bubbles" appearing when an attack lands and a blunt sound effect being heard, one can both hear and see the attack's visual effects as if there were no invincibility frames at all)
- The start of a Shield break
- Ike's Counter, only 1 frame
A character with intangibility will not be hit by attacks. For example, a projectile will travel right through them. Intangibility is often attributed to dodges, techs, edge-grabbing, get-up attacks and animations, and certain body parts during certain moves. Since the character is not hit, a long-lasting attack (or very short intangibility time) may still hit the character once it ends. Intangibility can also be called "dodging invincibility".
 Invincibility attacks
- Marth's Counter, only 1 frame.
- Roy's Counter, only 1 frame.
- Fox's Fox Illusion, only 1 frame.
- Fox's Reflector, first attack frame.
- Falco's Falco Phantasm, only 1 frame.
- Wolf's Reflector, first 6 frames.
- Zero Suit Samus' Flip Jump, only 1 frame
- Marth's Dolphin Slash, first 5 frames (5th frame is also hit frame, Brawl only).
- Mr. Game & Watch's Fire, frame 9 until frame 13.
- Sonic's up smash before the hitbox comes out.
- Pikachu's Thunder, beginning frames when Thunder strikes Pikachu.
- Zelda's Farore's Wind right before Zelda teleports.
- Sheik's Vanish right before Sheik teleports.
- Lucario's Double Team, during all the counter frames as well as the counter attack. Since it has true invincibility frames, it can protect Lucario from Final Smashes unlike other counters (though it still can't counter them).
- Jigglypuff's Rest, Approximately 20 frames after it's released, while its eyes are closing. (During the attack hitbox)
- All Final Smashes contain invincibility frames at one point during the move, if not for the entire final smash.
 Negative aspects
Invincibility's one negative aspect is that on the Planet Zebes, Brinstar and Norfair stages, characters will fall straight through the stage's lower hazard, rather than sustaining damage and bouncing back up.