When playing the 21+3 side bet in Blackjack, the second most desirable combination is known as a ‘Straight Flush’. It comes with a higher potential payout when compared to most other winning outcomes, such as a regular straight or flush. However, it’s still beaten by a suited three of a kind.
In this article, we dive into the straight flush part of a 21+3 side bet, covering exactly what it is, the payout rate, and the odds of one being dealt to players!
Table of Contents:
- Understanding the Blackjack Straight Flush Side Bet
- Blackjack Straight Flush Payout and Odds
- Conclusion
- Frequently Asked Questions about Blackjack Straight Flush
Understanding the Blackjack Straight Flush Side Bet
First things first, it’s important that players learn exactly what a blackjack straight flush is before they even consider laying chips on the 21+3 side bet.
What is a Straight Flush in Blackjack?
A straight flush in Blackjack is when the player’s two cards and the dealer’s face up card create a consecutive sequence, while also being the same suit. A few examples of a blackjack straight flush would be:
- The 2, 3, and 4 of hearts.
- The 8, 9, and 10 of spades.
- The J, Q, and K of diamonds.
It’s almost identical to a straight flush in poker. However, it’s formed with only three cards in Blackjack, as opposed to five.

How do you Place a Straight Flush Side Bet in Blackjack?
For anyone who wants to wager chips on a straight flush occurring in a hand blackjack, it falls under the 21+3 blackjack side bet. Players can simply place their desired stake size in the corresponding box, which is often found next to the main betting area.
Blackjack Straight Flush Payout and Odds
Now it’s time to touch on the potential winnings associated with a blackjack straight flush, while also looking at the probability of one being dealt to players.
What is the Blackjack Straight Flush Payout?
Should players be dealt a straight flush, their 21+3 blackjack side bet will be awarded at the rate of 40 to 1. This means that if players decide to wager £1.00, a total of £41.00 will be returned.
What are the Blackjack Straight Flush Odds?
The odds or probability of a straight flush sit at 0.0014%. This means that players would expect to be dealt a straight flush once every 72,193 hands but of course, this is not guaranteed.
What is the House Edge for a Blackjack Straight Flush Side Bet?
Now, while the probability of a straight flush occurring is relatively low in comparison to the likes of a regular flush or straight, it’s important to remember that players are wagering on all the following outcomes when laying chips on a 21+3 side bet:
- Flush

- Straight

- Three of a Kind

- Straight Flush

- Suited Three of a Kind

This means that in total, the 21+3 side bet comes with a house edge of approximately 6.00% to 9.00%, depending on the total number of decks that are used.
Conclusion
In conclusion, a blackjack straight flush is when three consecutively numbered cards of the same suit appear in the player’s hand and the dealer’s face-up card. It comes with a 40 to 1 payout rate and a 0.0014% probability of occurring, or 1 in every 72,193 hands. While this may seem incredibly unlikely, it’s also important to remember that the 21+3 side bet in Blackjack also covers a flush, straight, three of a kind, and suited three of a kind.
Here at Heart Bingo, we have a huge range of blackjack tables, many of which feature this entertaining side bet. Players can also find a selection of unique live blackjack variations in our extensive catalogue, including titles such as Quantum Blackjack Plus and Power Blackjack. While most of these tables follow the classic blackjack rules, they come with their own distinctive features!
Frequently Asked Questions about Blackjack Straight Flush
A straight flush in Blackjack is when the player’s 2 cards and the dealer’s face up card run consecutively, while also being the same suit. One example of this would be the 2, 3, and 4 of spades.
The Blackjack straight flush payout sits at 40 to 1, meaning that 41.00 would be returned if players wagered 1.00 on the 21+3 side bet.
Anyone who wants to place a bet on a straight flush occurring can lay their desired number of chips in the designated ’21+3′ area.
The odds or probability of a straight flush appearing in a round of Blackjack is roughly 0.0014%, which can also be represented as 1 in every 72,193 hands.
When looking at the house edge of a blackjack straight flush bet, players need to look at 21+3 as a whole, including the regular straight, flush, three of a kind, and suited three of a kind possibilities, too. This leads to the house edge sitting between 6.00% and 9.00%, varying slightly with the number of decks in play.



