Onyx Slots distributes promo codes more reliably than most UK-licensed casinos, and the value spreads across your first three deposits rather than dumping everything into a single sign-up offer. The standard welcome bonus — a 100% matched deposit up to £200 plus 50 free spins — requires no code at all. The codes listed below unlock a separate no-deposit bundle, a high-roller top-up, and the rotating reload offers that keep existing accounts ticking over between sessions.
| Code | Bonus | Type | Expiry | Who Can Use |
|---|---|---|---|---|
| ONYXWELCOME | 100% up to £200 + 50 Free Spins | Welcome Bonus | Ongoing | New players |
| ONYXFREE | 20 Free Spins — No Deposit | No Deposit | Limited | New players |
| ONYXRELOAD | 50% up to £100 | Reload Bonus | Weekly | Existing players |
| ONYXCASH | 15% Weekly Cashback | Cashback | Monthly | All players |
| ONYXHIGH | 75% up to £500 (min. deposit £300) | High Roller | Ongoing | New & existing players |
Deposit a minimum of £20 and Onyx Slots matches it pound for pound, up to £200. The 50 free spins credit to your account within 24 hours and run on Book of Dead at £0.10 per spin. You have 30 days to satisfy the 35x wagering requirement on the bonus portion, so a £200 bonus means you wager £7,000 through eligible slots before withdrawing. Maximum withdrawal from bonus winnings sits at £500. The ONYXWELCOME code is optional here — the welcome package triggers automatically on your first deposit.
Your second qualifying deposit earns a 50% match up to £150. The minimum deposit is again £20, and the same 35x wagering requirement applies to the bonus amount. You have 7 days from the moment the bonus credits to meet those terms. One thing worth flagging: Onyx Slots only counts stakes on slots towards clearing this particular offer — live casino tables and table games do not contribute.
Enter the code ONYXFREE during registration and Onyx Slots credits 20 free spins on Starburst before you deposit a penny. Each spin is valued at £0.10, so the total exposure is £2.00 worth of spins. Any winnings from those spins carry a 40x wagering requirement — win £5, and you need to wager £200 through eligible games before withdrawing. Maximum withdrawal from no-deposit winnings is £50.
Deposit £300 or more and enter ONYXHIGH at the cashier to trigger a 75% matched bonus up to £500. A £400 deposit returns £300 in bonus funds, giving you £700 to play with before wagering kicks in. The 35x requirement on £300 in bonus funds means clearing £10,500 through slots — substantial, but the ceiling on bonus winnings is £1,000, which makes the maths worthwhile for players who put in volume.
Onyx Slots sends personalised codes to registered accounts via email most Mondays — usually a reload offer of 40–50% on deposits made before midnight that day. The ONYXRELOAD code below works as a standing reload available through the promotions tab, giving a 50% match up to £100 on your next deposit. Cashback codes such as ONYXCASH come through once a month and return 15% of net losses across the preceding seven days, up to £75, with no wagering requirement attached.
Tip for existing customers: Onyx Slots sends reload codes via email — check your inbox every Monday morning. If you have opted out of marketing emails, update your preferences in your account settings or you will miss them entirely.
Beyond the deposit match sequence, Onyx Slots runs a rotating promotions calendar that rewards regular play rather than just sign-ups.
Every Monday, Onyx Slots calculates your net losses from the previous seven days and returns up to 15% as cashback, credited directly to your real-money balance with no wagering strings. The maximum weekly cashback payout is £200 per account.
Onyx Slots schedules slot tournaments on a rotating basis — typically one flagship competition per fortnight with a prize pool of at least £5,000 split across the top 50 leaderboard positions. Entry is free and prizes credit as withdrawable cash, not bonus funds.
The standing ONYXRELOAD code gives a 50% matched deposit up to £100, usable once per week. Stack it with a midweek deposit for the best return — Wednesdays tend to see the most consistent availability according to the promotions page terms.
Onyx Slots credits £25 in bonus funds for each friend you refer who deposits £20 or more within 30 days of registration. Your friend receives an additional 25 free spins on top of the standard welcome offer. There is no cap on the number of referrals per account.
Every £10 wagered on real-money slots earns one loyalty point. Collect enough points and Onyx Slots moves your account up through four tiers, each unlocking a better cashback rate and faster withdrawal processing times.
| VIP Tier | Points Required | Cashback Rate | Withdrawal Speed |
|---|---|---|---|
| Bronze | Starting level | 5% | Up to 48 hours |
| Silver | 5,000 points | 8% | Up to 24 hours |
| Gold | 20,000 points | 12% | Same day |
| Platinum | 75,000 points | 15% | Priority same day |
The promo code field appears twice during your journey at Onyx Slots: once on the registration screen and once inside the cashier deposit form. Codes entered during sign-up activate no-deposit offers. Codes entered at the cashier activate deposit bonuses. If you skip the field and complete a transaction without a code, Onyx Slots support can retrospectively apply it — but only within 24 hours of the deposit, and only if you raise the request via live chat before playing with those funds.
Onyx Slots accepts Visa and Mastercard debit cards, PayPal, Faster Payments via Open Banking, and Pay by Phone through Boku. Credit cards are not accepted for gambling deposits under UK Gambling Commission rules in force since April 2020.
| Method | Min Deposit | Processing Time | Notes |
|---|---|---|---|
| Visa / Mastercard Debit | £10 | Instant | Debit only — no credit cards |
| PayPal | £10 | Instant | Withdrawals back to PayPal in 0–12 hours |
| Faster Payments (Open Banking) | £10 | Instant | Bank-to-bank, no card needed |
| Pay by Phone / Boku | £10 | Instant | Charged to your phone bill; not available for withdrawals |
Onyx Slots processes withdrawals up to £3,000 per day, £7,500 per week, and £20,000 per month. Platinum VIP members receive priority processing on the same day. Standard accounts typically see PayPal withdrawals clear within 12 hours; bank transfers via Faster Payments take up to two business days.
A few things can catch you out if you miss them in the terms.