Bloom and Sky are a close couple but they have many ups and downs. This is the only couple where the girl has a known ex-boyfriend (Andy) and the boy has a known ex-girlfriend and fiancee (Diaspro) as it is unknown if the other couples have dated before or if their ex's will ever make an appearance. Sky asked Bloom if she would be his princess at the end of The Secret of the Lost Kingdom and asked her if she would marry him in Magical Adventure, both of which she accepted.
In Season 1, they meet for the first time and are quite close and they are both happy with each other, forming a strong and close friendship. At that time, Sky was pretending to be Brandon and vice versa.
Their relationship was a little shakey after Bloom found out that Sky and Brandon switched identies, and that he was engaged to Diaspro, but they were able to work past this and become close friends again during the attack by the Army of Darkness.
At the beginning of Season 2, Bloom and Sky have become closer but after hearing a rumor about Sky and Diaspro being together, Bloom is wary of her relationship with him. Sky assures her that nothing is happening between him and Diaspro. When Sky called her to meet up with him and have a serious talk, when in reality he was planning on asking her to be his girlfriend. Bloom agrees to meet him at Red Fountain but later starts thinking that he is going to break up with her. When the Trix attacked Red Fountain to obtain a part of the codex, Sky was hit with one of Icy's attacks. This put him in a suspended state where it seen like he died. Bloom is heartbroken and tries to revive him. She is successful and immediately afterwards Sky asks her to be his girlfriend to which she agrees. In Season 2, Bloom and Sky take part in a mission to rescue the Pixies. On the mission, the new girl, Aisha, impressed Sky with her survival skills and vice-versa. Though this was out of respect on both sides, it created tension between Bloom and Sky as Bloom got jealous of Aisha to the point of being slightly antagonistic towards her.Bloom developed a crush on the new Alfea teacher Professor Avalon (who was actually fake Avalon at the time). Sky took notice that Bloom spent most of her time with Avalon as he was helping her understand her past. During the unveiling of the new Red Fountain, Bloom left Sky and the Winx for Professor Avalon. Sky became jealous that Avalon was recieving so much attention from her and was becoming all that she would talk about when they were together.
Their relationship is very strained. As Sky tries to call her back, Bloom refuses to talk to him, even to the point of leaving a voice mail stating she would call back unless it was Sky.
Towards the end of the season, when Bloom was captured by Darkar, Sky took part of, if not led, the Rescue Mission to save her. In the Relix realm where the Winx and Specialists were paralyzed by Darkar's Magic, Sky was able to overcome his paralysis and make his way toward Dark Bloom. He was able to turn Bloom back to normal by telling her to fight back against her darkness, how he truly felt about her, and how he regrets he never spent enough time with her when he had the chance.
When they return back to Alfea, Sky looks for Bloom and finds her, and they both share a kiss at the end.
Sometime after Darkar's defeat, it is revealed that Bloom and Sky had a fight, and Bloom is noticably upset, not wanting to go on break until they talked. She is also upset at the fact that Sky was on his way to Eraklyon. However, due to an invite to Stella's Princess Ball, he was able to turn around and join Bloom and accompany her to the Princess Ball.
After they had made up, Sky plans to announce to his realm that he loves Bloom at his party on Eraklyon. However, it is disrupted and ruined by Diaspro. Diaspro gives Sky Valtor's spell and controls him, making him tell everyone that he loves Diaspro instead. Bloom attempts to talk to him, but due to be under a spell, Sky fights her instead.
Bloom is very upset, even taking a break from Alfea, but is convinced by Stella to come back to Magix and confront Sky. The Winx and Sky fight and Bloom realizes that he was under Valtor's spell.
The two reconcile before heading off to the Omega Dimension. Sky apologizes, and states that he couldn't control what he was doing, but Bloom forgives him. They are very close and happy.
When Bloom sends her dragon flame to defeat Valtor, she becomes lifeless, sending Sky to worry and be in tears. When Bloom returns to herself, Sky is happy and the two remain to keep a healthy relationship.Magic Dimension when Sky came there to comfort her. Bloom and Sky were later seen dancing in the fields of Alfea. Sky was telling Bloom something but he was disturbed by a ship from Eraklyon.
Later on, after Bloom dreamnt about Daphne telling her about amission to Domino, she later wakes up and goes into the living room and saw the Winx and the Specialists (minus Sky but came in as a surprise).
Bloom was still disturbed by the Eraklyon ship that picked Sky up earlier, fearing for the worst. Sky tries to explain what it was all about, but she tells him to explain after the mission since she didn't want to risk geting distracted emotionally. During the battle with Mandragora and the Ancestral Witches, after Stella, Flora, Tecna, and Aisha get defeated, Sky entered the dimension and pulled out the Sword of Domino despite Bloom's protests that doing so would kill him since he's only a prince. He apparently died from the sword's curse, devastating Bloom, but was taken by surprise when he suddenly got up to save her in time from a possessed Mandragora. Bloom then learned from Sky that the transport from earlier that picked him up was to get him to his coronation as King of Eraklyon, making him the "crownless king" in the legend, thus allowing him to use the Sword of Domino without hassle.
At the end of the movie when they have saved Domino Bloom has a princess ball, she dances with Sky. While dancing they pass by Stella and Brandon, Brandon passes a box to Sky which contains a ring. Sky whispers into Bloom's ear saying "will you be my princess?". Bloom says yes in the form of a loving kiss.
As Season 4 opens it is revealed that with Sky now being the King of Eraklyon, Bloom rarely has time to see him. When the Specialists arrive at Alfea to meet their girlfriends, Bloom feels sad that Sky is not there. Her attitude quickly changes as Sky is revealed to be hiding in the Specialists' ship. Their reunion is cut short as the Winx prepare to depart for Earth to find the last terrestrial fairy of Earth.
After the Winx set up their Love & Pet shop in Gardenia, Bloom's ex-boyfriend Andy shows up. He invites Bloom and the Winx to see his band perform at the Frutti Music Bar. Around the same time, Sky and the Specialists arrive in Gardenia under secret orders by Faragonda to help the Winx. Bloom, not knowing that Sky is in Gardenia spying on her, is seen hanging around with Andy. After seeing Bloom kiss Andy out of thanks, Sky assumes that Bloom still has really strong feelings for him and gets jealous. After fighting the Wizards of the Black Circle, Sky mentions to Bloom the Specialists' orders to help the Winx but also says he saw her with Andy. Bloom gets angry at him that he didn't trust her and for spying on her. She storms off with the rest of the Winx.
When the Winx fix up their apartment, Andy and his band stop by to see how its going. Stella mentions to Bloom that Andy is still into her which Bloom is surprised about. Sky and the Specialists (taking advice from Mitzi) appear sometime later to find the Winx with Andy and his group. Andy wanting to relieve the tension between everyone leaves but invites the Winx and Specialists to see his band play at the Frutti Music Bar. Sky then confronts Bloom about how close she and Andy are and storms off with the rest of the Specialists.
The two are seemingly at odds with each other at times, but they later reconcile after Bloom gets her Believix form and abilities.
Things were going great for Sky and Bloom as they are now engaged. However, when Sky's father, King Erendor, found out that Sky's intended is the Princess of Domino, he tells his son to cancel the engaement, much to his confusion and shock. He demanded to know why his father would ask him of such a thing, where he revealed a dark truth about his kingdom and its relation to Domino...
Bloom became devastated when her engagement to Sky was just cancelled, which her father, Oritel, took as an insult. As a result, Bloom was met with several possible suitors, none who could hold her interest. Finally, she was met by a disguised Sky whom she recognized and was in the midst of explaining what happened, but was caught by Oritel. Not giving Sky a chance to speak in his defense, he banishes him from Domino. Bloom is angered at her father's actions and leaves for Earth in retaliation as she didn't want to be near him for the moment.
On Earth, after Oritel finally managed to listen to reason thanks to Marion, tries to apologize to Bloom for what he did to Sky, but like he did with him, Bloom refuses to give him the time of day and bluntly states that she's going to meet up with Sky whether he approves or not.
The Winx and the Specialists took an airship to find the tree of magic, before it was overrun by dopplegangers. Bloom and Sky managed to successfully fight off their and each other's fakes. Even while kissing, they took down two dopplegangers trying to blindside them.
After the final battle once the Ancestral Witches and the Trix defeated, Oritel and Erendor make up, and give their children their blessings for their engagement.The Spill", Sky shows up with new changed hairstyle. Bloom appreciates the change. However, he plans to give her Pendant of Eraklyon two times before he finally lost it in a rescue action at oil rig. In that case, an old omen says if the crowned prince of Eraklyon loses the pendant,it means that he will never be happy with the girl he loves. From that time, Sky starts to avoid Bloom. Ultimately with his sacrifice for Bloom, he gets amnesia. From that moment, he treats Bloom like a stranger. In "The Sirenix Book", he still can't remember anything and eventually dismiss her during their walk.
In "The Shimmering Shells", Sky accompanied Bloom, Musa and Tecna in thier mission in saving Gardenia's Ocean. Later on, Bloom tells her to fight the sea monsters but doesn't know how to use a sword but later, he regained a bit of memory and uses that sword to save Bloom.
Later, he accompanies Bloom as well as Stella, Flora, and Aisha to Domino to attend a ceremony of Domino's revival (see Secret of the Lost Kingdom). Bloom tries to remind Sky that it was his courage that helped revived Domino from its icy prison, but he can't remember that. When the Trix attacks the castle and iced over Oritel and Marion, Sky managed to defend them from getting shattered. He and the Winx quickly fought off the Trix, then he and Bloom restored Oritel and Marion back to their real selves. It was also at that time Flora returned the Heart of Eraklyon back to Sky, who then instantly regained his memories. He finally presents the heart to Bloom.
Later, Diaspro abuses her new position as Erendor's liason to drive a wedge between Bloom and Sky. Working around the royal politics, Sky and Bloom were able to get in touch with each other at times, refusing to let anything or anyone get between them. Bloom gets a vision of herself and Sky holding each other tenderly when she was dancing before the magical mirror, thus opening her heart and earning her ballet shoes.
The Trix go to Gardenia and attacks Bloom and Sky, though without her friends, Bloom try's to fight with the Trix alone but fails to do so and falls unconscious. The Trix capture Sky and take him to the Infinite Ocean, where they tie him to the Throne and cast a spell on him so he was bound with the Emperor's Throne.
Bloom regains her consciousness. Flora tells her that something is going wrong in the Infinite Ocean and Stella asks Bloom where is Sky to which she answers that Sky has been kidnapped by the Trix and they took him to the Infinite Ocean. She tells them that they have to hurry to the Infinite Ocean to save Sky.In the Oblivion, Bloom wakes up in an empty room, and a dark illusion of herself appears and tells her that she has abandoned Sky but Bloom realizes that she was in the Oblivion. Sky wakes up and ask what happen to the Trix and Tritannus. Bloom says that the Trix fled and Tritannus is once again banished to the Oblivion and the pearl is back to where it should be. Then, Bloom and Sky kiss. Then, Kiko comes and gives an ice cream to Sky and he says he's dying for an ice cream and everybody laughs.
As a couple, Bloom and Sky have songs: