Australia captain Steve Smith and vice-skipper David Warner have been banned for a year for ball-tampering.
Cameron Bancroft, who carried out the cheating in South Africa, was given a nine-month ban by Cricket Australia.
The three had already been sent home from Australia's tour - before a fourth Test begins on Friday - amid widespread condemnation stretching beyond sport.
Australia's prime minister Malcolm Turnbull had said the affair "bitterly disappointed the whole nation".
Smith, 28, and Bancroft, 25, have also been suspended from captaining Australia for at least the next two years.
Warner, 31, will not be considered for "any team leadership positions in the future", Cricket Australia said.
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Cricket Australia's investigation also confirmed Bancroft used sandpaper to damage the ball during the third Test against South Africa.
It found Smith and Bancroft had made "misleading public comments" when on Saturday they instead claimed it had actually been yellow tape.
Cricket Australia had already concluded that coach Darren Lehmann was not involved in the controversy and he will remain in his post.
The body's chief executive James Sutherland said the three players were "sad, disappointed and remorseful".
He added: "This has caused damage to the game as a whole and certainly to Cricket Australia. It has compromised the fans' faith in cricket and it's our responsibility to reinstate that confidence.
"It appears to be an isolated incident but if there are other allegations we will take them further. There was some courage in owning up but there was an element of untruth and that's something we took into consideration."
Smith, Warner and Bancroft are banned from international and Australian domestic cricket. They will also serve 100 hours of "voluntary service in community cricket" and can appeal against the suspension.
Cricket Australia said the players would be "permitted to play [Australian] club cricket and will be encouraged to do so".
They also remain eligible for competition outside of Australia, but earlier on Wednesday Smith and Warner were also banned from this season's Indian Premier League.
In January the pair were signed to the most lucrative Twenty20 contracts ever offered to an Australian player - reportedly worth over £1m each.
Before Wednesday's IPL ban, Warner stepped down as captain of Indian Premier League side Sunrisers Hyderabad. Smith stood down as captain of Rajasthan Royals on Monday.
IPL chairman Rajeev Shukla said: "The players that they [Cricket Australia] have banned, we are also barring those two players from this season.
"The franchises will get replacements for the players."
Bancroft is due to play for Somerset this season. On Monday Somerset said they would wait and "collate all the relevant information before considering our next steps".
How did we get here?
After Bancroft's actions were exposed on Saturday, Smith admitted that the Aussie "leadership group" had devised a plan to tamper with the ball.
Images showed Bancroft take an item out of his trouser pocket before rubbing the ball with it.
After the game, Smith described the events as a "big mistake" but added he would not stand down as captain.
Following the conclusion of the third Test - South Africa won by 322 runs after an Australian batting collapse - the International Cricket Council (ICC) banned Smith for one match and fined him his entire match fee.
Bancroft was fined 75% of his match fee and given three demerit points, while Warner was not punished.
Having begun its own investigation after the match, Cricket Australia told reporters on Tuesday that it would look to sanction the players - in addition to the punishments by the ICC.
Australian cricket commentator Jim Maxwell told BBC Radio 5 live his understanding was that after lunch, Smith saw Bancroft and Warner in "collusion".
Maxwell said Smith had said to the pair: "What are you blokes doing? I don't want to know what you're doing", before then going out onto the field.
The charges in full:
Cricket Australia said Smith:
- knew of a potential plan to attempt to artificially alter the condition of the ball
- failed to take steps to seek to prevent the development and implementation of that plan
- directed that evidence of attempted tampering be concealed on the field of play
- sought to mislead match officials and others regarding Bancroft's attempts to artificially alter the condition of the ball
- made misleading public comments regarding the nature, extent and participants of the plan
The body said Warner:
- developed a plan to attempt to artificially alter the condition of the ball
- instructed a junior player to carry out a plan to take steps to attempt to artificially alter the condition of the ball using sandpaper
- provided advice to a junior player regarding how a ball could be artificially altered including demonstrating how it could be done
- failed to take steps to seek to prevent the development and/or implementation of the plan
- failed to report his knowledge of the plan at any time prior to or during the match
- misled match officials through the concealment of his knowledge of and involvement in the plan
- failed to voluntarily report his knowledge of the plan after the match
It found Bancroft:
- knew of the existence of, and was being party to, the plan to attempt to artificially alter the condition of the ball using sandpaper
- carried out instructions to attempt to artificially alter the condition of the ball
- sought to conceal evidence of his attempts to artificially alter the condition of the ball
- sought to mislead match officials and others regarding his attempts to artificially alter the condition of the ball
- made misleading public comments regarding the nature, extent, implementation and participants of the plan
Is this the end of the matter?
Several former players have raised concerns over the position of coach Lehmann. He was spotted in communication via walkie-talkie with the 12th man during the match against South Africa, leading to some to speculate he had been involved in a plan to cheat.
Former coach John Buchanan said it would have been "highly unusual" for Lehmann not to be aware of his players' plans.
However, Sutherland said Lehmann had been using the walkie-talkie to ask "what was going on?" and Cricket Australia was "satisfied he wasn't involved".
"I want to make that point very clear. Darren is the coach. He continues as coach under his current contract," Sutherland added.
"It appears to be an isolated incident but if there are other allegations we will take them further."
Former England captain Michael Vaughan had said he was "pretty sure" Australia were tampering with the ball during England's 4-0 Ashes series defeat.
The ICC has said it will not be investigating those claims, as the deadline for reporting any such offence has passed.
However, it is expected to discuss Australia's ball-tampering against South Africa at its next board meeting at the end of April.
Sutherland said while the South Africa incident "does appear to be isolated", Cricket Australia had the powers to investigate should further credible allegations arise.
The players involved could also suffer financial losses as sponsors seek to distance themselves from the matter - South Korean electronics company LG has already decided not to renew a sponsorship deal with Warner.
So was it cheating?
Sutherland had on Tuesday been reluctant to use the word 'cheating' when Cricket Australia announced that Warner, Smith and Bancroft would be sent home.
Despite being asked twice directly whether they had cheated or not, he instead said: "In the laws of the game, this is not in the spirit of the game. It is not a good day for Australian cricket."
On Wednesday he was asked the same question and replied: "I think people want to use their own words but certainly cheating is one of those that would be appropriate.
"It's compromised the fans' faith in cricket."
How big a loss are Smith and Warner?
Smith has been Australia's dominant player in recent years. In his 64 Test matches, he has scored 6,199 runs and made 23 centuries.
Named Test captain in 2015, he scored 687 runs as he steered his side to the recent 4-0 Ashes victory over England on home soil, leading to him being compared to legendary batsman Sir Donald Bradman.
Warner has been a more controversial figure. He was suspended for the majority of the 2013 Champions Trophy after punching England batsman Joe Root in a bar in Birmingham.
The left-hander was nicknamed 'The Bull' when he began his career but his team-mates began calling him 'The Reverend' after he gave up alcohol.
He was named vice-captain when Smith took over from Michael Clarke, and led Australia in Smith's absence in the recent Twenty20 tri-series against England and New Zealand.
Warner has a Test average of 48.20 after compiling 6,363 runs in 74 Tests.
He was fined after the first Test against South Africa for an altercation with Proteas wicketkeeper Quinton de Kock.
What will they miss?
Australia's schedule from the end of June has not been confirmed.
But all three players will miss the fourth Test against South Africa, which begins on Friday, and five ODIs and one Twenty20 on a mini tour of England this summer when the limited-overs series begins on 13 June.
Under the ICC's Future Tours Programme, which sets out when countries play one another, Australia could play India, South Africa and Sri Lanka in the period between October 2018 and January 2019.
They will all be eligible to play in the 2019 Cricket World Cup, which takes place in England and Wales from 30 May to 14 July.
The next instalment of the Ashes series is also scheduled to take place in the summer of 2019.