Last updated: May 2026. Based on 300+ test spins across four AU-friendly casinos plus the official Relax Gaming product page. Editor's verdict at the bottom.
Book of 99 is the pokie every Aussie spinner brings up in the same breath as RTP. Released by Relax Gaming on 4 May 2021, it carries a 99% RTP — the highest of any mainstream book-style slot in regulated markets, and a number you simply don't see attached to a game with a 12,075× ceiling. 5 reels, 3 rows, 10 fixed paylines, a Greek-mythology theme centred on Orpheus, one expanding symbol that covers entire reels during free spins, and high volatility — that's the package. The rest of this review explains why the math attracts pros, why the variance still drains casual bankrolls, and where to play it without getting clipped.
Skip the review and try it now▶ Play Book of 99 Real Money · 🆓 Free Demo · 🎁 Welcome Bonus
18+ · BetStop · gamblinghelponline.org.au · T&Cs apply
What is Book of 99?
A Greek-mythology book-style slot from Malta-headquartered Relax Gaming, built on the classic 5-reel, 3-row, 10-payline blueprint that started with Novomatic's Book of Ra two decades ago. If you're brand new to the game, our beginner's walkthrough takes you from cold to confident in five minutes. The visual identity centres on Orpheus, the lyre-playing poet of Greek myth who travelled to the underworld to retrieve Eurydice. Marble columns, a scrolling parchment book of secrets, and a moody temple soundtrack. None of that is unusual for the book genre. What is unusual sits in the paytable info: 99% RTP. Not 96%, not 96.5% — 99%.
That single number is what put Book of 99 on the radar of every advantage player, value-conscious recreational spinner, and AU streamer who actually pays attention to math. It's the same family of game as Book of Ra Deluxe and Book of Dead, but with a house edge roughly one-quarter the size.
Quick specs
| Spec | Value |
|---|---|
| Provider | Relax Gaming |
| Released | 4 May 2021 |
| Grid | 5 reels × 3 rows |
| Paylines | 10 fixed |
| RTP | 99% (market-leading) |
| Volatility | High |
| Bet range (AUD) | A$0.10 – A$100 per spin |
| Max win | 12,075× stake |
| Free spins | 10 (expanding symbol covers full reels) |
| Bonus Buy | Yes (in supported markets) |
| Demo available | Yes |
| Mobile | iOS, Android, browser |
| RNG cert | GLI / iTech Labs |
How Book of 99 actually plays
You set a stake, spin the 5×3 grid, and watch for two things. The first is the standard paytable — Orpheus is the top symbol, followed by his lyre, a winged-helm icon, a snake, and the usual book-genre card-rank low-pays (10, J, Q, K, A). Wins resolve left to right across the 10 fixed paylines.
The second, the thing that drives the game, is the golden book. The book is both the scatter and the wild. Three or more books trigger the free spins round. During free spins, one symbol is chosen at random as the expanding symbol — when it lands during the round, it expands to cover the entire reel, paying on every payline it touches regardless of adjacency.
This is the engine. Outside the free spins, you're playing a tight, traditional book slot at a 99% return rate — the highest-RTP mainstream slot in regulated markets. Inside the free spins, you're hoping the chosen expanding symbol is Orpheus (highest pay) and that it lands on multiple reels at once. That's the path to the 12,075× ceiling.
The free spins round
Land three or more golden books anywhere on the reels and you're awarded 10 free spins. Before the round begins, the book opens dramatically and one symbol is chosen as the special expanding symbol. From that moment, whenever that symbol appears during the round, it expands to fill the entire reel.
Practical math:
- Orpheus expanding on five reels = max-win territory.
- Orpheus expanding on three or four reels = several thousand× stake.
- Mid-pay symbol expanding (lyre, helm, snake) = a few hundred× — solid round.
- Card-rank symbol expanding = the round most players post screenshots of, complaining.
You can retrigger the free spins by landing three or more books during the round (extra 10 free spins added). The expanding symbol stays the same across retriggers.
This is the round where 12,075× hits happen. It's also the round where most sessions end with a sub-stake win.
Why the 99% RTP matters (and what it doesn't change)
A 99% RTP means the house edge is 1%. Over the very long run, a A$1 spin returns A$0.99 on average. Compared to a typical 96% slot (A$0.96), you're getting back roughly three extra cents per dollar spun. Over a 5,000-spin session, that's A$150 of additional expected return compared to a 96% slot at the same stake.
That said, 99% RTP does not mean you win. The variance is high, and the hit frequency on the base game is deliberately low — Relax Gaming pulled the small wins out to fund the bigger bonus-round payouts. In practical terms: expect long dry stretches in the base game, expect the free spins to land roughly once every 200-250 spins, and expect most free-spin rounds to deliver modest returns. The 99% lives in the average over millions of spins, not in your single Saturday-night session.
This is the trap. New players see "99%" and assume the game pays out constantly. It doesn't. The high RTP is real, but it expresses itself across the entire population of spins, not yours alone.
RTP variant warning
Like most modern slot studios, Relax Gaming ships Book of 99 in multiple RTP builds. The flagship 99% is the default in regulated EU markets and at the four casinos we feature. Lower variants exist at 96%, 94%, and 92% — casinos in less-regulated jurisdictions sometimes deploy these without flagging.
Always verify the RTP in the game's info panel before you spin real money. Click the (i) icon, scroll to the RTP field. If it reads anything other than 99%, you're playing a different game economically. All four casinos featured below (Vegasnova, Joe Fortune, GreatSlots, CasinoRocket) run the 99% certified variant at the time of our last verification (May 2026). The math of why 99% RTP actually matters is covered in its own deep-dive.
Why Aussies love it
The combination of 99% RTP + a known book-genre formula + a 12,075× ceiling is rare. Most ultra-high-RTP slots are simple, low-volatility games designed for wagering bonuses, with caps of 500× or less. Book of 99 is the opposite: high-RTP, high-volatility, with a max win you can actually scream about.
For AU pokie players who grew up on Book of Ra in land-based venues and have moved online, Book of 99 is the math-honest upgrade. Same gameplay loop, same expanding-symbol round, but with a house edge a quarter of what they're used to.
12,075× your stake is the ceiling. That's A$120,750 from a A$10 spin. Reachable when the expanding symbol is Orpheus and it covers four or five reels in a single round. Rare but documented — we break down the realistic odds in our 12,075× max-win analysis.
Where to play Book of 99 in Australia
The four casinos below are the ones we send Aussie traffic to from this site. Each was test-spun on Book of 99 before being added; details verified May 2026.
| # | Casino | Welcome Offer | Min Deposit | Wagering | Editor |
|---|---|---|---|---|---|
| 1 | Vegasnova | 100% match up to A$1500 + 100 spins | A$10 | 30x | 4.7/5 |
| 2 | Joe Fortune | 200% match up to A$1000 + 100 spins | A$20 | 35x | 4.5/5 |
| 3 | GreatSlots | 100% match up to A$500 + 50 spins | A$10 | 40x | 4.3/5 |
| 4 | CasinoRocket | 100% match up to A$1500 + 50 spins | A$20 | 35x | 4.4/5 |
Editor picks at a glance:
- Vegasnova — Best PayID withdrawals + full Pragmatic Play catalogue. Best if PayID-fast withdrawals matter to you.
- Joe Fortune — Long-running AU-focused brand with strong welcome bonus. Best for the welcome bonus value.
- GreatSlots — Slot-heavy library + A$10 min deposit. Best for low-stakes weeknight sessions chasing the 99%.
- CasinoRocket — High-stakes friendly with A$200/spin cap. Best for high-stakes spinners chasing the 12,075× ceiling.
For the full deep-dive on each — licence numbers, welcome-offer fine print, banking quirks, mobile UX — see our Best Australia Casinos to Play Book of 99 article.
Ready to open the book?▶ Play Book of 99 Real Money · 🎁 Claim Welcome Bonus
18+ · BetStop · gamblinghelponline.org.au · T&Cs apply per casino
Quick FAQ
Is Book of 99 legit? Yes — built by Relax Gaming, a Malta-licensed studio with RNG certification from independent labs. The 99% RTP is verified in the math sheet supplied to regulators. The casino you play at matters more than the game itself; stick to the four featured here.
What's the max win? 12,075× your bet. From a A$10 spin that's A$120,750. Reachable through the free spins round when Orpheus is the expanding symbol.
Is 99% RTP really the highest? It's the highest in the mainstream-slot category in regulated markets. A handful of niche games claim higher (some Mega Joker variants approach 99% with optimal play), but among modern video slots from Tier-1 studios, Book of 99 leads.
Can Aussies legally play it? Yes, at licensed offshore casinos. Australian operators don't offer real-money online slots under the Interactive Gambling Act, so AU pokie players use offshore-licensed sites (the four featured brands hold Curaçao licences).
Does 99% mean I'll win more often? No. Hit frequency is independent of RTP. Book of 99 has low hit frequency — the high RTP is delivered through bigger payouts when they hit, not through more frequent small wins.
Is the 12,075× max win realistic? It's the documented theoretical ceiling. In practice, most free-spin rounds land between 5× and 100×. The 12,075× hits exist (there are YouTube compilations) but they represent a tiny fraction of bonus rounds.
Does it have a jackpot? No fixed jackpot — the 12,075× max is achieved through the expanding-symbol mechanic in free spins, not a separate progressive pool.
About this review
This review was written by the Australia editorial desk after 300+ test spins across all four featured casinos plus the official Relax Gaming product page. RTP variants were verified in-game on each casino as of May 2026. Casino licence numbers and welcome offers were re-verified the same week. The four featured casinos are partners — we receive commission when players click through to deposit, but ranking is editorial: the order reflects our own AUD test sessions, not commercial weight. No casino paid for positioning.
The tracking link in our CTAs routes click traffic across the four casinos via a 25/25/25/25 split. Whichever brand the click lands on, the welcome offer detailed on that casino's page is what you'll see when you arrive.
Gambling responsibly. Set deposit and loss limits before you spin. 99% RTP is not a winning system — it's a long-term average across millions of spins. AU support: gamblinghelponline.org.au (24/7) · BetStop national self-exclusion register · 18+ only.
Further Reading
Continue exploring the cluster:
- How to Play Book of 99 — Beginner's Walkthrough
- Book of 99 Specs — Every Number That Matters
- Book of 99 Free Demo — Play Without Depositing
- Book of 99: Why 99% RTP Changes the Math
- Book of 99 Max Win — Chasing the 12,075× Ceiling
- Book of 99 Expanding Symbol — How Free Spins Pay
- Book of 99 Free Spins — 10 Spins, One Expanding Symbol
- Book of 99 vs Book of Ra — Which Book Slot Wins?
- Book of 99 vs Other 99% RTP Slots — The Honest Comparison
- Best Australia Casinos to Play Book of 99
- PayID & Banking for Book of 99 AU Players
- Book of 99 on Mobile