Over the course of the series, Reborn has worn many different outfits varying in design and culture. The ones known are listed below.
DoctorReborn's doctor costume. It is first seen during the Daily Life Arc when Reborn is trying to wake Tsuna for school. After the events of Tsuna confessing to Kyoko and fighting Mochida, he ends up having to shock Tsuna, which, as claimed by himself, is the "special Vongola way" of waking a person. Reborn wears a head mirror on his head and wears a pair of metal plates for letting electricity through.
Construction ManReborn's construction man costume. It was first seen during the Daily Life Arc when Reborn was tutoring Tsuna on mathematics. Reborn would detonate a bomb on Tsuna whenever the latter got an answer wrong. Lambo makes his debut at this tutoring time as well.
PajamasReborn's pajamas are first seen when Tsuna and Yamamoto were having test problems and the Family (Gokudera, Kyoko, Bianchi, and Haru) were trying to help them. Reborn sleeps at this time wearing this outfit, only waking to say a few words; however, he later wakes up to give the correct answer, prompting Haru's father to identify Reborn as Doctor Borin, a prodigious infant mathematician. Also, every night, Reborn is seen with this pajamas to sleep in.
Chestnut SuitReborn's chestnut suit was first seen when Gokudera claims that it was boring in the house. As a result, Reborn comes in this suit, the suit's name being a pun on words in Japanese. "Bikkuri" means "surprising", and "big kuri" means "big chestnut". Reborn uses this costume to spy on people who use trains for long distance commuting. People are scared of the spikes, so nobody bothers him. The costume was actually made by Bianchi when she was in elementary school for home economics class. The one who touches the spikes would go to heaven in 30 seconds, as claimed by Reborn himself. Reborn appeared as this costume again when Tsuna, Dino, Yamamoto and Gokudera went to Death Mountain.
Master PaoPaoReborn's "Master PaoPao" costume. A Thai boxing elder, PaoPao; although the one wearing is it actually Reborn in disguise. Reborn appeared as Master PaoPao again on top of a hippo named Saizou when Tsuna and Kyoko were on their first date.
Death GodReborn's death god costume. It was first seen worn by Reborn when Tsuna received the Skullitis disease from being shot by the Dying Will Bullet 10 times.
PandaReborn's panda costume, a costume first seen in the Daily Life Arc when Tsuna was looking for a babysitter for Lambo.
PriestReborn's priest costume. It was first seen in Tsuna's dream, the dream's shows being that the latter was marrying Kyoko with Reborn as the priest; however, the bride morphed into Haru instead.
Second CostumeReborn's second baseball-themed costume.
Hair StylistReborn's hair stylist costume. Reborn wears this outfit when helping Gokudera to combat wind resistance. Also, Leon is the comb.
New Year'sReborn's new year's costume, worn by Reborn when he gathered Tsuna's Guardians at the time (Gokudera, Yamamoto, Ryohei) to compete against Dino's Chiavarone Famiglia. Leon is the fan.
SamuraiReborn's samurai costume. Reborn wore this during the snowball fight at Namimori Middle when he was calling out the names of each team.
WarriorReborn's warrior costume, worn by Reborn during the three-way snowball fight.
CavemanReborn's caveman costume, Reborn's outfit when starting the second round of the snowball fight. Reborn appeared as this costume again when Tsuna, Dino, Yamamoto and Gokudera went to Death Mountain.
TrainerReborn's trainer costume, worn by Reborn when he and Dino are training Tsuna, Gokudera, and Yamamoto in the Death Mountain.
ExorcistReborn's exorcist Costume, a costume worn by Reborn when the nurse was getting sick of Tsuna's disruptions in the hospital. The nurse put Tsuna in a small, lab room full of insects and animals in jars. Reborn comes in with his exorcist costume and with the help of I-Pin, they come to exorcise Tsuna's room to remove his "evil spirit" that causing all of his injuries.
ChocolateReborn's chocolate costume, worn by Reborn when he asked Tsuna if he thinks that he'll get chocolates this year.
OfficerReborn's police officer costume, worn by Reborn when he sent Tsuna back home to prevent Bianchi from adding her Poison Cooking to Haru and Kyoko's food.
VongolavskyReborn's Vongolavsky costume, worn by Reborn to secretly assign Tsuna, Gokudera, Yamamoto and Kyoko in the same class; the school board also thinks that "Vongolavsky" is a special classroom assigner. Reborn used this costume to run all over Namimori Middle until Kyoko wins by catching him on top of the roof. With that, they get to be in the same class.
Professor BorinReborn's graduate costume. it was first seen during the Daily Life Arc. When Tsuna's group had trouble on problem #7, Haru call his dad for help. When he can't solve the problem, Reborn said that there is a answer to that problem. While Reborn was talking, Haru's Father noticed Reborn's sideburns, he recognized Reborn as Professor Borin, a mathematical genius that can solve every single problem previously considered impossible to solve. It was shown again when Borin was talking with the Principal and one of the staff members, right after Kyoko took the assigning clipboard from Reborn so they could assign themselves to the class that they wanted to be placed in.
FatherReborn's father costume, worn by Reborn when Hana goes to the Sawada household to ask more about the 15 year old Lambo.
GreekReborn's Greek costume, worn by Reborn when the residents of the Sawada household were going to Mafia Land for a vacation.
SwimwearReborn's swimwear, worn by Reborn when Tsuna's family and friends were trying to teach him how to swim.
FestivalReborn's festival costume, worn by Reborn during the Namimori Festival.
ClimberReborn's climbing suit, worn by Reborn when training Tsuna. DWM Tsuna chose to climb a mountain for practice to prepare for the Ring Battles with the Varia.
GentlemanReborn's gentleman costume, worn by Reborn when Tsuna fell off a cliff during his training for the Varia Ring Battles.
YukataReborn's yukata, worn by Reborn while Tsuna and his Family visited a hot spring.
Mr. RiboyamaReborn's teacher outfit, worn by Reborn when he took over Tsuna's class during the Open House. He started to teach the class because the teacher is busy taking care of Gokudera because he saw his sister, Bianchi.
PigeonReborn's pigeon costume, worn by Reborn during the Varia Arc when Haru was testing Tsuna to see if he's a good or bad person. He was spying on Haru with this costume with Bianchi holding him on her hand.
NinjaReborn's ninja outfit, worn by Reborn during the Varia Arc when popping up on the window when Tsuna was asking Dino about Hibari's fighting condition.
Old LadyReborn's old lady costume, worn by Reborn when he attended Tsuna's Open House at Namimori Middle School to look for candidates to be in Tsuna's family.
Fairy TutorReborn's fairy tutor costume, worn by Reborn 9 years and 10 months in the future while overseeing Tsuna and his Guardians training with Box Weapons.
GirlReborn's girl costume, worn when Reborn was supporting Kyoko and Haru's boycott, the former and the latter initiating the boycott because of being kept in the dark about the fight with the Millefiore Famiglia.
RebornbergReborn's director outfit, worn in the Reborn OVA's introduction; he refers to himself as "Rebornberg" in this costume.
TennisReborn's tennis costume, worn when telling Tsuna and Enma not to run away from the mafia.
SpiderReborn's spider outfit, worn during a Team Reborn meeting on the second day of the Representative Battle of the Rainbow.
GirlReborn's girl costume, seen in the episode where Shoichi Irie wanted to return the Bovino Famiglia's box to Lambo. Shoichi asked for Reborn and he saw Reborn as a girl.
Vongola Pizza DeliveryReborn's pizza delivery costume. It is first seen during the Daily Life Arc when Reborn wants Tsuna to be in the volleyball match. Reborn did this by poisoning the pizza, thus making the volleyball players unable to play and makes Tsuna a volleyball member.
CamouflageReborn's camouflage costume. It was first seen during the Daily Life Arc when Dino was explaining the training that happened when Reborn was his tutor. He wore a camouflage suit when Dino failed at fighting a bear with his whip.
Haiku ReadingReborn's haiku reading costume. It was first seen during the Daily Life Arc when Tsuna was sick with the Skullitis disease and it was almost time for Tsuna to die and Reborn was reading a haiku about Tsuna living a short life and ending in the sunset.
GrandpaReborn's grandpa costume. It was first seen during the Daily Life Life when Tsuna was done eating breakfast and leaving for school and Reborn was dressed like a old man eating the newpaper.
Tea ServingReborn's tea serving costume. It was first seen during the Daily Life Arc when Haru and Kyoko were having their once-a-month cake eating snack. After, Reborn offered Kyoko and Haru to Tsuna's house.
GroundhogReborn's groundhog costume. It was first seen during the Daily Life Arc when Tsuna's group were surrounded by a wildfire, caused by Gokudera's dynamites when Bianchi looked at him.
CupidReborn's cupid costume. It was first seen during the Daily Life Arc when Hana was thinking what made Tsuna so passionate to find out who Kyoko gave her chocolates to. Hana thinks cupid shot him with his arrow. And the cupid shown was Reborn.
HunterReborn's hunter costume. It was first seen during the Daily Life Arc when Reborn, Bianchi, and Lambo were eating the expensive sushi and they ran away because they didn't want to pay the bills. The bill was 70,000 yen. Because Tsuna didn't have that much money, Reborn, in his hunter costume suggested that he should work to pay the money off because Reborn said that a person who doesn't work doesn't deserve to eat. Reborn appeared as this costume when Tsuna was training to learn Zero Point Breakthrough: First Edition for the Varia Ring Battle.
Electric CatfishReborn's catfish costume. It was first seen during the Daily Life Arc when Tsuna gave up confidence on learning how to swim. This costume is instilled with lightning. Reborn used this costume to electrify Tsuna to not giving up.
DiverReborn's diving suit. It was first seen during the Daily Life Arc when Tsuna and this senior lifeguard was swimming for a race. Tsuna saw a little girl floating away to sea. Tsuna decided to risk his life to save that girl because when he was a kid, he floated away to sea and lifeguards saved him. When he reaches the girl, he sinks. Reborn, in his diving suit shot Tsuna with a Dying Will Bullet and saved the little girl.
Construction WorkerReborn's construction suit. It was first seen during the Varia Arc when Tsuna heard about Gokudera training by himself. He rushes over there and see Gokudera trying to throw dynamites, but can't because he was heavily damaged. Gokudera tries it one more time and fails, but luckily, Iemitsu dug a hole with Reborn to protect him.
Reborn's Elder Rebo suit. It was first seen during the Monster Tamer Tsuna series.