Book Of Sirens Slot Review
Toppled columns and arched colonnades blur in the deep teal, bubbles rise past a reel frame studded with gold filigree and turquoise, and somewhere in that murk sit two of the richest mermaids you’ll find on a 10-line reel set. That’s the real hook of Book Of Sirens: the paytable is weighted towards its premium end harder than almost any book game, with both mermaids paying from just two of a kind and the top line reaching half a hundred thousand times the bet. Spinomenal have put that ladder inside a drowned classical city, and it makes for an unusual combination: a rigidly familiar format wearing some of the lushest artwork in the genre.
It’s a 5×3 grid with 10 paylines, running at 96.14% RTP, and the richest line on the reels pays 50,000x the bet. The studio knows this format inside out, as Book Of Aphrodite and Story Of The Little Mermaid both show. What the sunken city keeps, it keeps below the surface.
The Base Game and Its Symbols
Wins form left to right across the 10 fixed lines, with only the highest combination on each line counting. The wild is a pearl-set book that stands in for any other symbol, and it doubles as the scatter, which is where the game’s real interest starts. That dual role is covered below.
The paytable splits into sea creatures and royals, and the two mermaids dominate it. All values below are multiples of the total bet:
- Pink-flowered Mermaid: 100x for two, 1,000x for three, 10,000x for four, 50,000x for five
- Purple-haired Mermaid: 50x for two, 400x for three, 4,000x for four, 20,000x for five
- Green Dragon: 50x for two, 300x for three, 1,000x for four, 7,500x for five
- Purple Octopus: 50x for two, 300x for three, 1,000x for four, 7,500x for five
- A / K: 50x for three, 400x for four, 1,500x for five
- Q / J: 50x for three, 250x for four, 1,000x for five
- 10: 250x for four, 1,000x for five
Those top-end mermaid numbers are steep for a 10-line game, and they only land at the top of the feature, not the base game. The gap between two-of-a-kind mermaid pays and three royal symbols is worth noticing: the paytable is weighted hard towards the premium end. Both mermaids pay from two of a kind, while every other symbol needs at least three. A buy button also sits next to the spin control, so the feature can be bought outright.
Two of the sea creatures sit a full tier below the mermaids, and the royals sit below them again. The dragon and the octopus pay identically, as do the A and K, so there are really five pay tiers rather than the symbol count suggests. That shape matters for the feature, because the wheel that picks the expanding symbol draws from every symbol except the wild, and what it lands on decides how the whole round pays.
Scatter Wild and Free Spins
The Scatter Wild
Three or more scattered wilds anywhere on the reels pay immediately, and those scatter prizes land on top of any regular line wins from the same spin. Landing them also starts the free spins. It’s a generous arrangement for a single symbol to carry.
- Three scattered wilds: 2x the bet, and 10 free spins
- Four scattered wilds: 25x the bet, and 10 free spins
- Five scattered wilds: 250x the bet, and 10 free spins
Free Spins and the Expanding Symbol
Triggering the round awards 10 free spins at the same bet per line as the triggering game. Before the spins begin, a wheel appears showing every symbol except the scatter wild, and one spin of that wheel selects the expanding symbol for the whole round. That’s nine possible outcomes, ranging from the pink-flowered mermaid at the top down to the 10 at the bottom.
Once each spin’s result is settled, the expanding symbol grows to cover its positions and forms new paylines on top of the existing ones. There are two conditions worth knowing: the expansion only happens when it will produce a win, and the expanded symbol pays across all active lines regardless of whether the winning symbols sit on consecutive reels. Expanded wins count separately from the original result of the spin.
That second condition is the one to hold on to. On a normal line win, symbols have to sit on consecutive reels from the left. In the feature, the expanding symbol ignores that requirement entirely, so a scattered handful of matched symbols across reels one, three and five still pays as though they sat together.
The order of events on each free spin runs in a fixed sequence. The base result lands first and any regular line wins pay out. Then the expanding symbol covers the reels, and its separate paylines are evaluated and paid on their own. Nothing is lost from the first result to fund the second, which is what makes a screen full of the chosen symbol pay twice.
Retriggers
The round can extend itself. Free spins may retrigger, and each retrigger adds another 10 free spins to the running total, with the same expanding symbol carrying over. Because the scatter wild doesn’t appear on the expansion wheel, retriggers are the only way the round grows. Chain a few of them with the pink-flowered mermaid as the expanding symbol and the non-consecutive payline rule starts doing serious work, because every fresh spin gets another chance to scatter the mermaid across all five reels and pay her on all 10 lines at once.
Our Honest Verdict
Overall Rating: 7.1/10
Playing Book Of Sirens is a long drift through beautiful water waiting for one symbol to surface. That’s the whole appeal: the pearl-book does everything, and when enough of it arrives, the round that follows is where every coin in this sunken city is kept. The artwork deserves the wait more than most.
The feature is the strength, and it’s a real one. The expanding symbol paying on non-consecutive reels means a scattered handful of mermaids pays like a full screen, and with retriggers stacking more spins under the same symbol, the ceiling climbs fast. The weakness is the shape around it: one mechanic, one round, and a base game that’s mostly a tide chart between triggers.
It suits players who already like book slots and want a prettier one, and it’ll leave anyone hunting varied features cold. The sirens only know one song, but the reef they sing it on is lovely.
Book Of Sirens FAQs
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What is the RTP of Book Of Sirens?
Book Of Sirens runs at an RTP of 96.14%. -
How many paylines does Book Of Sirens have?
Book Of Sirens has 10 fixed paylines, with wins paying left to right and only the highest combination on each line counting. -
What is the grid size of Book Of Sirens?
Book Of Sirens plays on a 5×3 grid: five reels and three rows. -
How do you trigger free spins in Book Of Sirens?
Landing three or more scattered wild symbols anywhere on the reels triggers 10 free spins. The scatter wilds also pay 2x, 25x or 250x the bet for three, four or five respectively, on top of any line wins. -
How does the expanding symbol work in Book Of Sirens?
At the start of free spins, a wheel of all symbols except the scatter wild is spun to select one expanding symbol. During the round it expands after each result, but only when the expansion creates a win, and it pays across all active lines whether or not the winning symbols are on consecutive reels. Expanded wins are paid separately from the original result of the spin. -
Can free spins retrigger in Book Of Sirens?
Yes. Landing more scatter wilds during the round adds another 10 free spins, and the expanding symbol chosen at the start stays the same throughout. -
Can you buy the bonus on Book Of Sirens?
Yes, a buy button sits next to the spin control, so the free spins feature can be purchased directly rather than waited for. -
When was Book Of Sirens released?
Book Of Sirens was released on 3 April 2022.
