Three carrier-billing payment service providers are live at UKGC-licensed casinos in 2026: Boku (one operator, Casushi), Fonix Mobile plc (two operators, MrQ and Hot Streak Casino), and Siru Mobile (one operator, Mr Vegas). Payforit, the legacy carrier-billing scheme, no longer markets itself as a standalone PSP, and its rails now sit underneath Boku and Fonix.
Every one of those casinos is an online casino licensed by the UK Gambling Commission, and the payment side runs through a direct carrier billing provider regulated separately. This page maps each PSP to the operators that actually use it, sets the caps, fees, and minimum deposits side by side, and shows you how to tell which provider is behind your favourite casino before you deposit. The comparison table in the next section lays all three out, attribute by attribute.
The UK pay-by-phone PSP landscape in 2026
A UK pay-by-phone casino is funded through one of three carrier-billing PSPs in 2026: Boku, Fonix Mobile plc, or Siru Mobile. Each is a direct carrier billing provider, and each sits at a different number of UKGC-licensed operators.
The universe is small and easy to state. Boku is at Casushi only. Fonix is at MrQ and Hot Streak Casino. Siru is at Mr Vegas. Payforit, the legacy fourth name, isn't a separately marketed PSP any more, and its underlying rails were absorbed into the Boku and Fonix carrier-billing flows. So that's four UKGC-licensed operators across three active providers.
Here's how the three active providers compare, attribute by attribute.
| Attribute | Boku | Fonix Mobile | Siru Mobile |
|---|---|---|---|
| UK regulated entity | Boku Account Services UK Limited (FRN 900030, FCA EMI) | Fonix Mobile plc (LSE:FNX, Companies House 05836806) | Siru Mobile Oy (Finnish parent, no UK-incorporated entity) |
| Wikipedia knowledge-graph anchor | Yes (Boku, Inc.) | Yes (Fonix Mobile plc) | No, bridges to Direct carrier billing |
| UK operator count (May 2026) | 1 (Casushi) | 2 (MrQ, Hot Streak Casino) | 1 (Mr Vegas) |
| Headline minimum deposit | £10 | £10 | ~£5 (£5.12 gross after Siru's 25% fee on a £4 net) |
| Daily limit | £30 (Boku carrier cap) | £40 (Fonix PSPA-set carrier ceiling) | £40 carrier ceiling, subject to fee uplift |
| Monthly limit | £240 | £240 | £240 |
| Carrier-side fee uplift | None | None | 25% to 33% at the carrier-merchant layer |
| Bonus eligibility | Operator-dependent, verify | Operator-dependent (MrQ and Hot Streak flag yes) | Operator-dependent (Mr Vegas flags yes) |
| Withdrawal direction | Deposit-only, one-way | Deposit-only, one-way | Deposit-only, one-way |
One constraint binds all three. None of Boku, Fonix, or Siru can route winnings back to your phone bill, because carrier billing is a one-way payment route under UKGC anti-money-laundering rules and the Payment Services Regulations 2017. The cap on a withdrawal isn't the issue. The route simply doesn't exist.
And the list keeps shrinking, for a clear reason. Remote Gaming Duty doubled from 21% to 40% on 1 April 2026, which squeezed thin-margin operators out of carrier-billing integrations, per the HMRC gambling duty changes. Carrier billing serves a small share of total deposits but needs an active commercial integration per PSP, so it's an easy cost to cut. One quick note on the numbers: the OLBG comparison cites a £40 daily limit while Boku publishes £30, and both are right, because the £40 is the Fonix and Payforit carrier ceiling under PSPA rules and the £30 is Boku's own commercial cap. The next three sections go PSP by PSP. You can read more on our Boku casinos UK and Fonix casinos UK pillars, or on how pay by phone deposits work.
Boku at UK casinos in 2026: Casushi only
Casushi is the only UKGC-licensed UK operator with a confirmed live Boku integration in May 2026. It's operated by Solaya Group Limited under UKGC account 100050, with a £10 minimum Boku deposit confirmed on the Casushi banking page.
The corporate structure behind Boku is worth getting right, because affiliate sites routinely point at the wrong entity. The parent is Boku, Inc. The FCA-authorised arm is Boku Account Services UK Limited, registered as an Electronic Money Institution under FRN 900030, and that's the entity that clears carrier-billed casino deposits. A separate group company, Boku Network Services UK Limited (Companies House 05044979), handles trading and integration but isn't the FCA-authorised arm, so any regulatory claim points to Account Services.
Boku's UK caps come as a set: an £8 ceiling on the first transaction, then £30 a day and £240 a month, reproduced on the Casushi banking page. The £30 daily limit binds across every Boku-billed gambling merchant, not per casino, so a second Boku account doesn't unlock a second allowance. Casushi is also Sky Mobile compatible, since Sky Mobile runs on the O2 network.
The Casushi-only finding is the freshness moat. As recently as 2024, Sky Vegas, Virgin Games, Foxy Bingo, and other UKGC brands took Boku, and the post-April-2026 Remote Gaming Duty doubling has cut the active Boku universe to one. We re-verify the operator universe quarterly, and most affiliate rosters haven't caught the contraction. For the full picture, see our Boku casinos UK pillar and the UKGC and pay-by-phone responsible gambling page.
Fonix Mobile plc at UK casinos: MrQ and Hot Streak Casino
Fonix Mobile plc is the carrier-billing PSP behind MrQ and Hot Streak Casino, two of the four UKGC-licensed pay-by-phone casinos active in May 2026. The other two are Casushi on Boku and Mr Vegas on Siru.
Fonix is a serious corporate entity, not a back-office processor. It's listed on the London Stock Exchange's AIM market under ticker FNX, admitted on 12 October 2020, incorporated in England under Companies House registration 05836806, and founded in 2006. By Fonix's own corporate statement, it's the largest SMS and carrier billing mobile aggregator in the UK, and its client roster spans ITV, Comic Relief, Children in Need, and Channel 5. That diversification matters as a credibility signal for a YMYL comparison.
MrQ is operated by Tek Fox Ltd under UKGC account 60629, takes Fonix Pay by Mobile at a £10 minimum, and flags those deposits as bonus-eligible, per the OLBG pay-by-phone casinos listing. The Fonix flow confirms with a 4-digit SMS PIN, and that PIN step is the carrier-side authorisation point. Hot Streak Casino also takes Fonix Pay by Mobile, at a £10 minimum, and its deposits are eligible for promotions. The Fonix carrier-billing ceiling is £40 a day and £240 a month under Phone-paid Services Authority rules, though Hot Streak sets a lower £30-a-day cap of its own, per the OLBG listing. But Hot Streak's Fonix integration rests on the OLBG public-source bridge, so treat it as confirm-at-cashier until a logged-in check proves it out.
Fonix has arguably overtaken Boku in the 2026 UK landscape, and the metric is simple. Two UKGC-licensed operator integrations against Boku's one inverts the historical Boku-primary, Fonix-secondary framing. The Fonix carrier-billing daily ceiling of £40, set under Phone-paid Services Authority rules, also sits above Boku's £30, which matters for higher-stakes players at the headline-limit layer. For the deeper treatment, see our Fonix casinos UK pillar, and compare it against the Boku casinos UK page.
Siru Mobile at UK casinos: the niche alternative at Mr Vegas
Siru Mobile is the third UK pay-by-mobile PSP, used by Mr Vegas Casino as of May 2026. It's a Finnish-origin direct carrier billing provider with no Wikipedia entity of its own, so it bridges upward to the Direct carrier billing category, and its headline minimum is £5.12 with a 25% to 33% carrier-side fee added on top.
The corporate identity is thinner than Boku's or Fonix's by design. Siru Mobile Oy is the Finnish parent, it runs as a niche carrier-billing PSP across several European markets with UK gambling as one vertical, and it has no UK-incorporated entity in its own name. There's no standalone Wikipedia article in English or Finnish, which is why every Siru reference here bridges to the canonical Direct carrier billing entity rather than standing alone.
Mr Vegas Casino is operated in the UK by Videoslots Limited under UKGC account 39380, and it accepts Siru Mobile as its named pay-by-mobile method, bonus-eligible, at a headline £5.12 minimum, per the OLBG listing. Its sister site Videoslots Casino also takes Siru, but it sits outside our four-operator UK universe, so we don't list it.
Two things set Siru apart from Boku and Fonix. The first is the sub-£10 headline minimum, the only one at any UKGC operator in 2026. The second is the fee, and it's the catch worth understanding: Siru adds 25% to 33% at the carrier-merchant layer, so a £4 net deposit shows as a £5.12 charge on your bill, and a £14.55 net deposit shows as £18.90. Pay-by-Boku and pay-by-Fonix carry no equivalent uplift. So the £5.12 entry point isn't really cheaper than the flat £10 elsewhere once you do the per-pound maths. For the mechanics behind that, read how pay by phone deposits work, or go back to the canonical pay by mobile casino guide.
Why Payforit isn't a separately marketed PSP in 2026
Payforit was the legacy UK carrier-billing scheme run collectively by EE, O2, Vodafone, and Three. It closed to new merchants by 2024 and isn't marketed as a separate PSP any more, and its rails now sit underneath the Boku and Fonix flows.
The brand-to-rails transition is the part most pages miss. Payforit was an industry-collective scheme sitting on the four operators' shared infrastructure. Boku and Fonix are commercial PSPs that layered on top of that same MNO carrier infrastructure rather than replacing it, so when the Payforit brand wound down, the underlying rails persisted, branded as Boku Pay by Mobile or Fonix Pay by Mobile depending on the operator. The £40 daily and £240 monthly figures cited for Fonix come from the same PSPA-set carrier-billing ceilings Payforit ran under, so there's regulatory continuity even where the merchant brand changed.
Some older casino aggregator pages still list Payforit as a separate option. But that's out-of-date content, not a live PSP, and the same goes for PayViaPhone, which no UK casino markets as a named method in 2026, per the OLBG comparison.
Which PSP is at your favourite casino, and how to check before depositing
Three carrier-billing PSPs are live at UKGC casinos in 2026: Boku at Casushi, Fonix at MrQ and Hot Streak Casino, Siru at Mr Vegas. Before you deposit, verify which PSP your operator's cashier actually uses, because they aren't interchangeable. Here's the three-step workflow.
- Check the operator's banking or cashier page. Most UKGC operators name the PSP explicitly, as "Pay by Mobile (Fonix)" or "Boku" or "Siru Mobile". If the page only says "Pay by Mobile" with no provider named, go to step 2. The banking page usually lists carrier compatibility alongside the PSP, which you can cross-reference against our mobile carrier compatibility matrix.
- Open the pay-by-mobile flow at the cashier. The SMS PIN-confirmation message itself usually names the provider. A Fonix flow says "Fonix" in the sender ID or the confirmation copy, a Boku flow says "Boku", and a Siru flow says "Siru". The sender ID is the most reliable identifier when the banking page is ambiguous.
- Cross-check against an affiliate aggregator. Sites like OLBG name the PSP in their per-operator coverage. But beware of stale content, because affiliate pages older than six months may not reflect the post-2026-RGD contraction.
That aggregator caveat is worth dwelling on. Plenty of UK affiliate pages still list Sky Vegas, Virgin Games, or Foxy Bingo as Boku-accepting, and as of May 2026 none of those three takes Boku, against the post-April-2026 Remote Gaming Duty doubling and the live Casushi banking page. So use the operator's own banking page as the canonical source, and treat our PSP-by-operator map as a quarterly-refreshed cross-check.
The PSP you land on changes what happens at the wallet layer. At Casushi on Boku, the £30 daily cap binds across every Boku-billed merchant, so a second Boku account doesn't buy a second allowance. At MrQ or Hot Streak on Fonix, the £40 daily cap is the Fonix and PSPA ceiling, with the same cross-merchant logic. At Mr Vegas on Siru, the £5.12 minimum is gross of the 25% to 33% fee, so roughly £4 of every £5 reaches your balance. For the deposit-and-withdrawal mechanics in full, see pay-by-phone casino deposits and withdrawals.
FAQ: Boku vs Fonix vs Siru at UK casinos
- Who uses Boku payments?
- Boku Account Services UK Limited (FRN 900030) is the FCA-authorised Electronic Money Institution within the Boku group, used by UK consumers through their mobile network (EE, O2, Vodafone, Three, plus supported MVNOs like Tesco and Sky Mobile) to fund UKGC-licensed casino deposits. Giffgaff and Lebara block gambling carrier-billing in their own terms, and Asda Mobile is conditional. In May 2026, the only UKGC operator with a live Boku integration is Casushi.
- Is Boku a safe payment method?
- Yes. Boku Account Services UK Limited (FRN 900030) is FCA-authorised as an Electronic Money Institution under the Payment Services Regulations 2017 and the Electronic Money Regulations 2011, and operators using Boku must hold a UKGC licence. The £30 daily and £240 monthly Boku UK cap is a built-in spending ceiling that predates the October 2025 UKGC deposit-limit mandate.
- Should I use Boku or Fonix at a UK casino?
- Use whichever PSP your chosen UKGC operator accepts, because they aren't interchangeable. In 2026, Boku is at Casushi only, Fonix is at MrQ and Hot Streak Casino, and Siru is at Mr Vegas. Fonix's £40 daily cap is higher than Boku's £30, and Siru adds a 25% to 33% carrier-side fee, so the choice follows the casino, not the other way round.
- What's the difference between Boku, Fonix, and Siru?
- Boku and Fonix are the two dominant UK direct carrier billing PSPs. Boku is an FCA-authorised EMI within the Boku, Inc. group, and Fonix Mobile plc is the LSE-listed (FNX) largest SMS and carrier-billing aggregator in the UK by its own corporate statement. Siru Mobile is a Finnish-origin niche PSP used at one UK operator, Mr Vegas, with a 25% to 33% carrier-side fee uplift.
- Which UK casinos accept Boku in 2026?
- Casushi (Solaya Group Limited, UKGC account 100050) is the only UKGC-licensed UK casino with a confirmed live Boku integration in May 2026, at a £10 minimum deposit. For the wider context, see our Boku casinos UK pillar.
- Which UK casinos accept Fonix in 2026?
- MrQ (Tek Fox Ltd, UKGC account 60629) and Hot Streak Casino both take Fonix Pay by Mobile at a £10 minimum, with the £40 daily and £240 monthly carrier-side ceilings, and Pay-by-Mobile-eligible welcome bonuses. Our Fonix casinos UK pillar covers both in depth.
- Can I withdraw winnings to my phone bill with any of these PSPs?
- No. Boku, Fonix, and Siru are all deposit-only. Carrier billing is a one-way route under UKGC anti-money-laundering rules and the Payment Services Regulations 2017, so winnings can't travel back to a mobile bill. Withdrawals route to a registered debit card, bank account, or e-wallet on your casino account.
- Why has the UK pay-by-phone casino universe shrunk to four operators?
- The 1 April 2026 Remote Gaming Duty doubling, from 21% to 40%, accelerated cost-cutting at thin-margin UKGC operators. Carrier-billing integrations serve a small share of deposits but need an active commercial integration per PSP, so they were among the first costs cut, and Sky Vegas, Virgin Games, and Foxy Bingo all dropped Boku between 2024 and 2026.