Online Caribbean 21 is a RealTime Gaming blackjack variant, one of RTG's older table titles and the game Wikipedia names in connection with a 2004 dispute at Hampton Casino. Its RTP and rule card aren't published by independent sources, so here is what is on record, what to confirm in the game before you bet, and how bonuses and US law apply.
That's close to the full public record. No independent source we could verify publishes the game's RTP, rules, release year, volatility or maximum payout. Treat the rule discussion below as a checklist for the help screen, not a description of RTG's version.
If you play other RTG 21 games, you'll know the basics already. The online blackjack page covers the standard game, and our online casino games hub lists every RTG table title we cover.
Caribbean 21 and the 2004 Hampton Casino dispute
Wikipedia's Realtime Gaming article names Caribbean 21 in connection with a 2004 dispute at Hampton Casino. The sources available to us don't give enough detail to describe what happened or how it ended, so we won't guess.
The broader lesson still applies. Disagreements over game results and payouts do happen, and at offshore casinos the player has fewer places to take them. There's no US state regulator to complain to, and outcomes depend on the casino, its license holder, if any, and any independent mediator it accepts.
If a hand seems wrong, stop playing and note the time, table, bet and result.
Take screenshots of the game screen and your balance, and download or screenshot the game history if the casino offers one.
Contact support in writing (live chat transcript or email) and ask for the hand to be reviewed.
Ask which body licenses the casino and whether it accepts outside dispute resolution.
Blackjack variants differ in a handful of rules, and each one moves the house edge. Open the game's help screen and fill in this table before playing for money.
Caribbean 21 odds: estimating cost without a published RTP
The cost formula is the same for every game: expected loss = total amount bet × house edge. For Caribbean 21 the house edge isn't published, so look for a stated RTP in the help screen or ask support for it in writing.
For a sense of scale, RTG blackjack games with published figures sit high: PokerListings lists Super 21 at 99.6%, and SlotCatalog lists Suit 'Em Up Blackjack at 99.51%. Those are different games with different rules, so they don't tell you Caribbean 21's figure; they show what a well-paying blackjack looks like in dollars.
What $2,000 in total bets costs at published RTG blackjack RTPs
Game
Listed RTP
Expected loss on $2,000
Source type
Super 21
99.6%
$8
Third-party (PokerListings)
Suit 'Em Up Blackjack
99.51%
$9.80
Third-party (SlotCatalog)
Caribbean 21
Not published
Unknown
None found
Remember that blackjack RTPs normally assume perfect decisions. Guesswork or hunches add to the cost. Our house edge explained guide shows how much.
Caribbean 21 strategy: why Martingale doesn't work
Blackjack's near even-money bets make it a magnet for doubling systems. The Martingale says to double your bet after every loss so that one win recovers everything plus one unit. Here's what that looks like from a $5 start.
Martingale from a $5 base bet
Losses in a row
Next bet
Total lost so far
Profit if the next hand wins
0
$5
$0
$5
3
$40
$35
$5
5
$160
$155
$5
7
$640
$635
$5
9
$2,560
$2,555
$5
You risk hundreds or thousands to win $5, and a table maximum or an empty balance ends the sequence with a large loss. Losing streaks of this length are uncommon on any given run but certain to occur over enough play. The system changes the shape of your results, not the house edge. Our is Martingale a good strategy page has the full math.
Card counting doesn't help either. It relied on used cards staying out of play in a physical shoe, while online RNG blackjack reshuffles every hand. See card counting online for the history and theory.
Caribbean 21 vs RTG's other 21 games
RTG's table range includes several blackjack relatives. GamblingNews lists Face Up 21, Match Play 21 and Pontoon among RTG's table games, without rules or RTP data. If Caribbean 21 isn't in your casino's lobby, one of these, or standard blackjack, usually is.
RTG blackjack relatives and what's published about them
Game
Published detail
Source type
Caribbean 21
Named in a 2004 dispute (Wikipedia)
Third-party
Super 21
Six decks, 99.6% RTP
Third-party (PokerListings)
Suit 'Em Up Blackjack
99.51% RTP, 3:2 blackjack, dealer hits soft 17
Third-party (SlotCatalog, GamesHub)
Blackjack + Perfect Pairs
95.9% to 99.59% RTP
Third-party (GamesHub)
Face Up 21, Match Play 21, Pontoon
Named only; no rules or RTP
Third-party (GamblingNews)
Playing Caribbean 21 with a casino bonus
Blackjack is the game bonus terms restrict most often. SlotoCash's welcome terms allow only slots, Real-Series slots (not progressives), keno and scratch cards, and say play on other games voids promotion winnings. Third-party reviews describe Slot Madness's eligible games as slots and keno. LCB reports Royal Ace's wagering as 30x on slots and parlor games but 60x on blackjack and classic blackjack.
At 60x, a $100 bonus would need $6,000 of blackjack bets if the multiple applied to the bonus alone; LCB reports Royal Ace's multiple applies to bonus plus deposit, which doubles that on a matching deposit. Every dollar wagered costs the house edge on average. Read wagering requirements explained and our table games bonus guide before you combine them.
Is online Caribbean 21 legal in the US?
That's a question for your state's law. Only New Jersey, Pennsylvania, Michigan, West Virginia, Delaware, Connecticut and Rhode Island license real-money online casinos, and RTG games aren't offered in those licensed markets. Maine legalized tribal online casinos in January 2026, but none had launched by October 2026 and a lawsuit is pending.
Caribbean 21 is therefore found at offshore casinos, which no US state licenses or regulates. Federally, UIGEA targets payment processing for unlawful internet gambling rather than making a bet a federal crime for the player. Our is online gambling legal in the US page and guide to state cease-and-desist letters explain how states respond to offshore sites.
Where to play Caribbean 21: RTG casinos with an offer via our links
These three casinos run RTG or SpinLogic software, according to third-party reviews. No source confirms Caribbean 21 in their lobbies, so check the table games section before depositing. They're offshore casinos, not licensed by any US state; check your state's law first. We earn commission from these links, and the order is commercial, not a test result.
Royal Ace Casino: $2,500 Welcome Bonus + 35 Free Spins, via our link (new players, 21+ or 18+ where allowed, terms apply).
Slot Madness Casino: $2,500 Welcome Bonus + 50 Free Spins, via our link (new players, 21+ or 18+ where allowed, terms apply).
SlotoCash Casino: $6,000 Welcome Bonus + 60 Free Spins, via our link (new players, 21+ or 18+ where allowed, terms apply).
Royal Ace's terms couldn't be read, and third parties disagree: LCB's Royal Ace listing (opens in a new tab) reports 200% up to $4,000 with 30x (bonus + deposit) on slots, 60x on blackjack and video poker and a max cashout of 10x the deposit, while Casino Guru reports 250% up to $2,500 plus 35 spins without a wagering figure. Third-party reviews report Slot Madness's code MAD275 at 275%, a $30 minimum deposit, 30x (bonus + deposit) on slots and no max cashout. SlotoCash publishes its bonus terms (opens in a new tab): 25x (deposit + bonus), $20 minimum deposit per bonus, $10 max bet and no max cashout on the welcome package; its own site advertises $7,777 + 300 spins, which differs from the offer via our link.
The Michigan Gaming Control Board named Slot Madness in orders on August 14, 2025 (opens in a new tab) and SlotoCash in letters announced October 8, 2026, calling them illegal offshore operators. Some third-party reviews also report that Royal Ace and Slot Madness don't accept players from Ohio. The terms shown at sign-up apply. Read the Royal Ace review, Slot Madness review and SlotoCash review first, and call 1-800-MY-RESET (1-800-697-3738) if gambling is causing problems.
Ad21+ (18+ where allowed). Ranked by us in a commercial order; we earn commission from these links. Advertiser disclosure
This is a blackjack game, so check how each casino's bonus terms treat blackjack before you opt in.
Royal Ace Casino#6 on our listSlots and specialty games
Published terms (reported): Third-party reviews disagree on the package (200% up to $4,000, or 250% up to $2,500 + 35 spins); the casino site could not be checked directly. Eligible games: Slots and specialty games (reported).
Who runs it: License not shown; third parties report Costa Rica or none. Regulator notes: Third parties report it does not accept Ohio players.
21+ (18+ where allowed). New players. Min deposit $30 (reported). Wagering 30x deposit + bonus on slots (reported). Max cashout: 10x deposit (reported). Withdrawal cap $2,500 / week (reported). Terms source: reported. Terms apply. Offer checked October 28, 2026.
Published terms (reported): Third-party reviews report a 275% match up to $2,750 with code MAD275; the casino site could not be checked directly. Eligible games: Slots and keno (reported).
Who runs it: License not shown; third parties report Anjouan, Costa Rica or none. Regulator notes: Named in a Michigan Gaming Control Board cease-and-desist release, August 14, 2025.
21+ (18+ where allowed). New players. Min deposit $30 (reported). Wagering 30x deposit + bonus (reported). Max cashout: None (reported). Withdrawal cap $2,500 / week (reported). Terms source: reported. Terms apply. Offer checked October 28, 2026.
SlotoCash Casino#1 on our listBiggest bonus on our list
Published terms (casino terms): SlotoCash advertises up to $7,777 + 300 spins over five deposits on its own site. Eligible games: Slots, keno and scratch cards (progressive jackpots excluded).
Who runs it: License not shown on its site; reported as a Deckmedia N.V. brand (Curaçao). Regulator notes: Named in a Michigan Gaming Control Board cease-and-desist release, October 8, 2026.
21+ (18+ where allowed). New players. Min deposit $20 per bonus. Wagering 25x deposit + bonus. Max cashout: None stated. Withdrawal cap $5,000 / week. Terms source: casino terms. Terms apply. Offer checked October 28, 2026.
These casinos are offshore operators. They are not licensed or regulated by any US state, and state consumer protections do not apply. Check the law in your state before you play. Terms marked “reported” come from third-party reviews; the terms shown at sign-up apply.
21+ (18+ where allowed). Every casino game has a built-in house edge, so over time you should expect to lose what you stake. Set a budget before you play and stop when it’s gone: responsible gambling tools and free help. Gambling problem? Call or text 1-800-MY-RESET (1-800-697-3738).
Frequently asked questions
What is Caribbean 21?
It's a blackjack variant from RealTime Gaming, offered at casinos that run RTG software. Wikipedia names it in connection with a 2004 dispute at Hampton Casino. Its RTP and full rules aren't published by independent sources, so read the game's help screen for the payout, dealer and doubling rules before you bet. Our online blackjack page covers the standard game it builds on.
What is the RTP of Caribbean 21?
No RTP for Caribbean 21 is published in any source we could verify. Look for a stated return in the game's help screen or ask support in writing. For comparison, PokerListings lists RTG's Super 21 at 99.6% and SlotCatalog lists Suit 'Em Up Blackjack at 99.51%, but those are different games with different rules. See what is RTP for how to read the figure.
What happened with Caribbean 21 at Hampton Casino?
Wikipedia's Realtime Gaming article names Caribbean 21 in connection with a 2004 dispute at Hampton Casino, but the sources available to us don't give enough detail to describe it reliably. The practical point is that game disputes happen, and at offshore casinos you have no state regulator to turn to. Keep records of any disputed hand, and see our how to file a casino complaint guide.
Is Caribbean 21 the same as Caribbean Stud?
No. Caribbean 21 is a blackjack variant, while Caribbean Stud Poker is a five-card poker game played against the dealer. RTG also offers Caribbean Hold'em, another poker-based game. The shared word is a naming theme, not a shared rule set, so check each game's help screen for its own rules and returns before you play for money.
Does the Martingale system work in Caribbean 21?
No. Doubling after each loss doesn't change the house edge; it trades many small wins for occasional very large losses. Starting at $5, nine losses in a row means a $2,560 bet to win back $2,555 and make $5, and table limits or your balance can stop you first. Our is Martingale a good strategy page shows the full calculation.
Can I count cards in online Caribbean 21?
No. Card counting depended on used cards staying out of a physical shoe until the reshuffle, and online RNG blackjack reshuffles every hand, so there is nothing to track. Basic strategy, matched to the game's actual rules, is the only legitimate way to lower the edge, and it never removes it. Our card counting online guide explains the history and theory.
Can I clear a bonus on Caribbean 21?
Usually not efficiently. SlotoCash's welcome terms exclude games other than slots, keno and scratch cards, and third-party reviews report Slot Madness's eligible games as slots and keno. LCB reports Royal Ace's blackjack wagering at 60x, double its slot rate. Always read the terms shown at sign-up and ask support how Caribbean 21 is classed. See game weighting explained.
Where can I play Caribbean 21 online in the US?
Only at casinos running RTG or SpinLogic software, which are offshore and not licensed by any US state. State-licensed casinos in New Jersey, Pennsylvania, Michigan and the other licensing states don't carry RTG games. Check your state's law, confirm the game is in the lobby and read the casino's terms before depositing. Our best blackjack casinos list covers the partners we rank.
Can I play Caribbean 21 on my phone?
If a casino carries it, you'd play Caribbean 21 in a mobile browser rather than through an app. SlotoCash's own support page says no app or software is required, third-party reviews report browser play on Android and iPhone at Slot Madness, and AskGamblers lists Royal Ace with instant play and mobile access. None of those sources confirms Caribbean 21 in a lobby, so search the table games list after you log in. Open the help screen on your phone too, because the rules checklist on this page matters just as much on a small screen. See our mobile casino guide and what is instant play.
How can I find the house edge of Caribbean 21 before I play?
Start with the game's own help screen, since no independent source publishes Caribbean 21's RTP. Look for a stated return percentage, then write down the blackjack payout, the dealer's soft 17 rule, doubling and splitting limits and the deck count. If no RTP is shown, ask live chat for it in writing and save the transcript. Once you have a figure, expected loss is total bet times the edge: at a 0.5% edge, $2,000 of bets costs about $10. Compare it with Super 21's listed 99.6% on our Super 21 page, and read how to read casino terms.
How long do Caribbean 21 withdrawals take at Royal Ace?
Third-party reports suggest anything from about a week and a half to more than a month. AskGamblers reports a pending period of 7 to 10 days at Royal Ace, then 10 to 14 days for bank transfers, with no weekend cashouts, while LCB says payouts are usually issued after a month or more. Reviewers report a $2,500 weekly cap, a $20 minimum and no withdrawal fees, and list bank wire, check and Bitcoin as methods. Verify your account before you request so documents don't add time. Read the Royal Ace withdrawals page and our casino withdrawal delays guide.
Is Caribbean 21 legal to play online in Georgia?
No state law in Georgia authorizes online casinos, so there's no licensed way to play Caribbean 21 or any online blackjack for real money there. Georgia has no casino or sports betting regulator; the Georgia Lottery Corporation runs the lottery only. The RTG casinos that carry Caribbean 21 are offshore, so a Georgia player would have no state body to complain to about a disputed hand or a stalled payout. The Georgia Crisis and Access Line, 1-800-715-4225, is listed for gambling help. Read our Georgia online casino guide and can I play online casinos in Georgia.
Should I take insurance in Caribbean 21?
If Caribbean 21 offers insurance, the standard math says no. Insurance pays 2:1 when the dealer has blackjack, and with 4 of every 13 cards worth 10 under the infinite-deck approximation, it loses about $0.38 on every $5 staked, roughly 7.7%. That's many times the cost of a well-played main hand at RTG's published blackjack figures, such as Super 21 at 99.6%. Whether Caribbean 21 offers insurance or even money at all isn't published, so check the help screen. Read our insurance glossary entry and the online blackjack page for the full calculation.
Are Caribbean 21 winnings taxable in the US?
Yes, blackjack winnings from Caribbean 21 are taxable federal income, even at an offshore casino. For table-style wagering, the IRS instructions for Form W-2G tie reporting to winnings that meet the $2,000 threshold and are at least 300 times the wager, so most blackjack wins never produce a form. The tax is still owed whether or not an offshore casino issues a W-2G. Keep a simple log of dates, deposits, withdrawals and results. From the 2026 tax year, the loss deduction is reported to be capped at 90% of losses; check IRS guidance. See keeping gambling records and gambling taxes.
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