Summary
Luffy is the protagonist ofOne Pieceand, of course, a character that fans hold very close to their hearts. Luffy has grown tremendously as a pirate over the years and he has achieved this by engaging in many high-risk battles.
Luffy has fought quite a lot of strong opponents on his way to becomingone of the Yonko of the Seaand he has certainly been put in near-death situations on countless occasions. While Luffy has, most of the time, triumphed over his enemies, the fact that he could have died many times just goes to show how difficult his journey has been.

9Sunk In Baratie
During the Baratie arc ofOne Piece, Luffy ended up defeating Don Krieg, the man who claimed to be the mightiest in the East Blue. When Luffy defeated him, he was trapped in a net and dropped directly into the ocean.
He would certainly have plummeted to his death given that he is a Devil Fruit user. He was only able to survive thanks to Sanji, who jumped into the ocean immediately after him and saved his life on instinct.

8Fighting Crocodile
Luffy fought against Crocodilefor the first time outside Rain Dinners in Arabasta. This clash did not last long and Crocodile gave him 3 minutes to showcase what he could do. Naturally, Luffy failed largely fighting against Crocodile’s Logia powers.
While Luffy certainly tried his best, he was outsmarted and outclassed easily and, at the end of it all, stabbed right through his gut using the hook that Crocodile wielded on one of his hands.

7Fighting Lucci
Another time when Luffy was put in a near-death state waswhen he fought against Lucci.This time, he put his body into overdrive in an attempt to defeat an enemy who was stronger than him at the time. Luffy relied on the usage of Gears and, eventually, it put so much stress on his body that he could not move at all.
Had it not been for Usopp, would most likely have died in the Buster Call right there and then. Thankfully, he was able to move once again and defeat Lucci. Yet, after he defeated Lucci he could, once again, not move. It was Robin who rescued him and dropped him into the sea and Merry, who came to save the crew, did the rest.

6Destroyed On Sabaody Archipelago
Luffy and the entirety of the Straw Hat Pirates were utterly destroyed on Sabaody Archipelago, after Kizaru was sent to the island because Luffy punched a Celestial Dragon.Kizaru would certainly have killed every single memberof the crew or, at the very least, taken them as prisoners.
Thankfully, Rayleigh and Kuma showed up to help the crew and, even though Luffy was bruised and battered and completely crushed mentally, he survived.

5Poisoned By Magellan
Luffy broke into Impel Down to rescue his brother, Ace, after finding out about his planned execution. It was only natural that he was going to come up against the Head Warden of the prison and, when that happened, the Devil Fruit powers of Magellan proved to be way too great for him to deal with.
Magellan controlled poisons with his Doku Doku no Mi and he poisoned Luffy to a point where he could not have been saved by normal means and would certainly have died had it not been for Ivankov and his own conqueror spirit.

4Scarred By Akainu
In the Paramount War, Luffy was thrown into a battle where he certainly did not belong. Luffy was far too weak to compete on this front yet, he did his best to save his brother. In the end, Ace ended up dying and Luffy was put in a state of shock.
Although he was saved by the Whitebeard Pirates and Jinbe, Akainu almost killed him. Had it not been for Jinbe, Luffy would definitely have died. In fact, even after surviving this, the mental shock that he suffered was so great that he could very well have died from it.

3Blood Loss On Fishman Island
Luffy demonstrated his incredible power on Fishman Island after the 2-year timeskip. Even though defeating Hody was easy for him, the fact is that he ended up receiving injuries that caused him to lose a lot of blood.
Luffy could have died on Fishman Island from blood loss and, had it not been for Jinbe, who shares the same blood as Luffy, the straw hat pirate would have died immediately after returning from the timeskip.

2Defeated By Enraged Army
On Whole Cake Island, Luffy faced yet another defeat. This time, he was faced with the Enraged Army of Big Mom. Having already been beaten by Sanji at this point, Luffy did not have it in him to fight this powerful army of numerous high-bounty fighters.
They absolutely bruised and battered him to the point where he passed out and was, later on, locked in the prison book of Mont d’Or. Once again, it was Jinbe who saved the day by rebelling against Big Mom and saving Luffy.

1Killed By Kaido
Luffy actually ended up dying once in the story and that waswhen he fought against Kaido.Due to interruption from CP0, Luffy took the brunt of Thunder Bellowing Bagua directly to his face. This crushed him completely and put him in a state of death. His heart was not beating and even Kaido mentioned that Luffy had died.
His body and voice had both given out, as confirmed by multiple characters. However, in this state of death, Luffy rebirthed. His Devil Fruit awakened and his heart started beating as the Drums of Liberation. It was the return of Joyboy and, for the first time in 800 years, this legendary warrior, Nika, finally returned.