There are thirty coins to be found in Sirena Beach. Some are outside the hotel, some are inside, and a few are in the casino. Since you can't enter the hotel in every episode, and only enter the casino in two episodes, location is important when you select and episode to find a coin.
To make locating the hotel rooms a bit easier, label them from left to right A-F for the floor above the lobby, and G-K for the next floor up. So taking the stairwell to be north, go up one flight from the lobby to find A, B and C on the east wall, D on the south wall, and E and F on the west wall. Then go up another flight to find G and H on the east wall, I in the southeast corner, and J and K on the south wall, with the rest of the floor being taken up by the pool. You can reach every room in every episode except 1, 2, and 6, see the walk-throughs for episodes 3 and 8. But it's easiest to just wait until episode 7 when all the room doors are open.
Visible, outside (x3)
Ocean floor
Go to the left end of the beach and keep following the cliff to the left until the water starts to get deep. Dive and look around for the coin that's on the ocean floor. Available every episode.
Cabana ceiling
Head toward the hotel and look under the roof of the cabana on the right to find a blue coin and a gold coin. Hop on the bar and hop again to get the coins. Available starting episode 2.
Hotel ledge
Go around to the back of the hotel. There will be a blue coin sitting on a ledge one floor up. To reach it, back-flip into the wall behind the hotel and wall jump toward the hotel, then hover to the ledge. Available starting episode 2.
Visible, hotel (x4)
Room A
Find a blue coin in a row with two gold coins in the bedroom. Available all episodes except 1, 2, 6.
Room B
Find a blue coin in a square with three gold coins. Available all episodes except 1, 2, 6.
Room H
Find a blue coin in a rectangle with five gold coins. Available all episodes except 1, 2, 6.
Attic cul-de-sac
Get up the attic by bouncing on the bed in room K. Go clockwise to the next corner and get to the second passage in from the outer edge. Find a coin in the cul-de-sac where the passage ends. Available all episodes except 1, 2, 6.
Graffiti, outside
Cabana M
Go toward the hotel to the cabana on the right. Check the wall behind and to the right of this to find a graffiti M. Wash it off go get a coin. Available starting episode 7.
Graffiti, hotel (x6)
Stairwell M
Go to the top floor and check the wall between the pool and the stairwell for a graffiti M. Wash it off go get a coin. Available starting episode 7.
Attic M
Get up the attic by bouncing on the bed in room K. Get around to the other side of the skylight and find the small room next to it. Check the wall behind four gold coins for a graffiti M. Wash it off go get a blue coin. Available starting episode 7.
Paired crosses (x2)
Locate the graffiti cross on the hallway wall left of room F. Then locate a corresponding cross on the hallway wall between rooms G and H. Wash one cross off to make a blue coin appear at the other cross, then quickly get to the other cross to collect the coin before it disappears. The crosses are on different floors but they are both close enough to the stairwell that you can rush up or down it to get to the other location in time. To save time and avoid confusion caused by changing camera angle, stand next to the stairs when you do the washing. Available starting episode 7.
Paired triangles (x2)
Locate the graffiti triangle on the wall on the lobby opposite the front desk. It's in a lounge area with a fruit stand at one end. Then locate the corresponding triangle on the hallway wall between rooms C and D. Wash the graffiti and rush to get the coins. This time the symbols are far enough away from the stairwell that it's probably impossible to get from one location to the other using it. To get from the upper location to the lower one just drop over the balcony, being careful not to land on one of the burning torches below. To get from the lower location to the upper one, stand next to the totem pole when you wash the triangle, this takes longer but it doesn't matter. Then when the coin pops out quickly switch to hover, do a back-flip into the totem pole, wall kick up, and hover to the balcony. This is tricky and may take a few tries. Available starting episode 7.
Graffiti, casino
Casino M
Enter the casino and immediately turn around and look up to spot a graffiti M over the entrance. Wash it off go get a coin. You might think this would be visible in episode 4 since you go through the casino then, but no. Available episode 5 only.
Miscellaneous washing, outside (x?)
Unlucky Noki (x2)
In episode 1, starting from the beach, hop up the ledge to the right to a tree with a fountain moat around it. Wash the goop off the ground between the moat and the cabana to rescue a Noki couple. In episode 6 the same couple needs rescuing again, wash the ground behind the lawn chairs to the left of the same tree. Wash them clean and talk to them to get a blue coin from each as a reward. Available episodes 1 and 6 only. Can be repeated for 1-ups.
Slightly Lucky Noki (x2)
Starting from the beach, hop up the ledge to the left to a tree with a fountain moat around it. Wash the goop off the ground between the moat and the cabana to rescue a Noki couple. This couple escaped the goop from episode 1, making them slightly luckier than the unlucky Noki couple. Wash them clean and talk to them to get a blue coin from each as a reward. Available episode 6 only. Can be repeated for 1-ups.
Hotel sign
Starting from the beach, hop up the ledge and spray a small, square sign in front of the lawn chairs to make a coin pop out. Available starting episode 2.
Douse the flame
Notice the eight flames burning in braziers in front of the hotel. Spray the second one from the left to get a blue coin. You get a gold coin if you spray one of the other seven or one of the two flames on the ledge above. Available starting episode 2.
Miscellaneous washing, hotel (x?)
Room G
Spray the mirror over the bed to make a blue shine logo appear. When the logo is fully formed a blue coin pops out. Available all episodes except 1, 2, 6.
Room I
Spray the empty shelves on the left (next to the upturned couch) to make a coin pop out. Available all episodes except 1, 2, 6.
Hidden, hotel (x?)
Room C
Break the box closest to the doorway leading to room B to get a coin. Available all episodes except 1, 2, 3, 6.
A blue coin is near the start point. Go straight and there is a standing block in front of you. Squirt it from the other side, and there's a blue coin!
Before you enter the hotel, spray the fires surrounding the hotel and one of them should have a blue coin.
All 30
- Underwater off the coast of the beach (all episodes). Ocean floor
- Spray the sign overlooking the sunset (all episodes). Hotel sign
- Spray the second torch from the left in front of the hotel (all episodes). Douse the flame
- Clean the M Graffiti by the hotel (episodes 7 and 8). Cabana M
- Water the sunflower garden beside the hotel (episodes 2 thru 8).
- Underneath a hut (episodes 2 thru 8) Cabana ceiling
- Outside the hotel on the back of the second floor (episodes 2 thru 8). Hotel ledge
- (Now inside) Corresponding Triangle marks [floors 1 and 2] (episode 7 and 8). Paired triangles
- Same as above (episode 7 and 8). Paired triangles
- Corresponding X marks [1F and 2F] (episode 7 and 8). Paired crosses
- Same as above (episode 7 and 8) Paired crosses
- Spray the skylight [3F] (episodes 3,4,5,7,8)
- M Graffiti [3F] (episodes 7 and 8). Stairwell M
- Spray the lamp [3F] (episodes 3,4,5,7,8)
- In the room behind the Boo poster [Attic to 3F] (episodes 3,4,5,7,8) Room H
- Go back to the room, and spray the empty bookcase [3F] (episodes 3,4,5,7,8). Room I
- From there, Ground Pound the different colored tile [3F to 2F] (episodes 3,4,5,7,8) Room B
- Smash the box in the next room [2F] (episodes 3,4,5,7,8) Room C
- Defeat the Boo [Attic] (episodes 4,5,7,8)
- Go to the middle of the Attic and spray the M graffiti (episodes 7 and 8) Attic M
- In the air duct [Attic] (episodes 3,4,5,7,8). Attic cul-de-sac
- From the Attic, find the room with the mirror and spray the mirror [Attic to 3F] (episodes 3,4,5,7,8) Room G
- From there, Ground Pound the table for to find a blue coin [3F to 2F] (episodes 3,4,5,7,8) Room A
- (Back outside) Wash the two Nokis (episode 6) Noki
- Same as above (episode 6) Noki
- (Inside) M Graffiti above the door [Casino] (episode 5) Casino M
- Ground Pound the slot machines [Casino] (episodes 4 and 5)
- Put out the torch [Casino] (episode 4 and 5).
- Clean the Nokis (outside) (episode 6) Noki
- Same as above. (episode 6). Noki
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