21.co.uk Casino Sister Sites

Short answer: 21.co.uk does have real sister sites, and they are unusually easy to confirm because they all sit on one company’s gambling licence. The site is run by LeoVegas Gaming PLC, which is owned by MGM Resorts International. And — this is the part most “sister sites” pages get wrong — 21.co.uk is not an offshore casino. It is licensed in Britain by the Gambling Commission, so the usual offshore warnings do not apply to this brand. What follows is the verifiable version, with the register entries you can check for yourself.

Who actually runs 21.co.uk

Behind the brand is a single licensed operator: LeoVegas Gaming PLC, registered at Level 7, Plaza Commercial Center, Bisazza Street, Sliema, Malta. LeoVegas is not independent — MGM Resorts International acquired the group in 2022 in a deal worth roughly $600 million. So the ownership runs in layers: brand (21.co.uk) → operator (LeoVegas Gaming PLC) → parent (MGM). That layering matters more than it sounds, because the brands underneath LeoVegas share their plumbing: the same licence, the same account, and the same customer-protection duties.

21.co.uk began as one of a cluster of UK-facing sites LeoVegas absorbed years ago (grouped internally under the “Rocket X” label). It runs today as a casino under the LeoVegas licence rather than as a company of its own.

What is, and isn’t, verifiable about the licence

Here the register does the work. On the Gambling Commission’s public register, 21.co.uk is listed as an active domain under LeoVegas Gaming PLC, account 39198, licence number 039198-R-319450-029. The casino part of that licence has been active since 1 November 2014, alongside bingo and betting permissions. The licence belongs to the operator directly — it is not borrowed from a separate white-label “platform” company — and you can read the entry yourself rather than take an affiliate’s word for it on the Commission’s register for account 39198.

One honest limit: I could not load 21.co.uk’s own footer from outside the UK to quote its on-site licence statement, because the site geo-restricts access. The operator and licence details above come from the Commission’s register, which is the authoritative source in any case.

The verified sister sites

The clean way to find 21.co.uk’s true siblings is to look at which other domains sit on the same account (39198). Those are its real sisters — same operator, same licence, same complaints and self-exclusion system. Anything else that affiliate round-ups throw in (“similar casinos you might like”) is marketing, not family.

All five are listed as active domains on the same register entry as 21.co.uk. The entry also shows older, now-inactive domains (such as leovegas.com and a couple of bingo sites) that no longer trade under this licence, which is why they are not counted as current sisters.

What sharing one licence means for you

Because these six brands run on a single licence, they behave as one for the things that protect a UK player:

• Self-exclusion carries across them. If you exclude through the national online self-exclusion scheme, or directly with the operator, that block covers 21.co.uk and its sisters together. You cannot open Slot Boss to sidestep a 21.co.uk exclusion, because it is the same account behind both.
• Deposit limits are per account, not shared. A limit you set on 21.co.uk applies to that account only. Opening a separate account on a sister brand starts a fresh limit, so if you are managing spend, set one on each brand you use.
• You get a genuine complaints route. As a UK-licensed operator, LeoVegas must handle disputes and give you access to an independent, Commission-approved dispute-resolution (ADR) service if you cannot settle things directly. Offshore sites offer no such route — which is precisely why the licence is worth checking.
• Bonus terms still vary brand to brand. A shared owner does not mean shared offers. Read each brand’s wagering rules on its own terms page. UK rules cap wagering requirements on incentives at 10×, but the rest of the small print differs between sites.

Don’t mix it up with the offshore look-alikes

This is where the confusion comes from, and probably why you may have seen 21.co.uk wrongly labelled “offshore”. A separate brand called 21 Casino (on 21casino.com) is run by a different company altogether, White Hat Gaming — it is not a sister of 21.co.uk and does not share its licence. There are also unlicensed sites that borrow the “21” name and point players toward Curaçao-registered casinos. If a site using the “21” name will not show a UK Gambling Commission account number you can find on the register, treat it as offshore: no UK complaints route, no self-exclusion cover, and no UK fund protection. Check the exact domain and the register entry before you deposit.

The verdict

21.co.uk is the reassuring case rather than the risky one: a UK Gambling Commission-licensed casino run by LeoVegas under MGM ownership, with a short, verifiable list of genuine sisters all sitting on the same licence. That is the opposite of an offshore setup, and it is the reason its family is so easy to confirm. If you ever land on a “21” site that cannot point you to a UKGC account number, take it as your signal that you have drifted onto something unlicensed — and a licensed site is the safer place to play.

18+. If gambling stops being fun, free and confidential help is available from GamCare on the National Gambling Helpline, 0808 8020 133.