Blue Coin #15 and #16
On the first floor of the hotel, on the right side from the entrance, there is a triangular-shaped piece of graffiti. The other piece of graffiti is found on the second floor, on the back wall. Getting the coin on the first floor is easy, as you can just drop down in the opening. However, getting the coin on the second floor is a bit more complicated, as taking the stairs will cause the timer to run out. Instead, spray the graffiti on the first floor, then wall jump and hover from the central totem pole.
Blue Coin #17 and #18
On the second floor, in the main lobby portion, there is an X-mark graffiti on the one wall. The other one will be on the third floor. The trick with the other pair won’t seem to work here, since the totem pole is a little out of reach. However, you should have just enough time to get to the third floor coin if you spray the graffiti from the stairs. When the coin spawns on the second floor, try to spray the graffiti from the little lip surrounding the stairs, as this allows you to just quickly drop down to the stairs.
Blue Coin #19
On the third floor of the hotel, there is the usual piece of graffiti on the one wall in the main portion. Clean it to get the Blue Coin.
Blue Coin #20
On the third floor of the hotel, there is a lamp in the far back of the main portion, by the room with the open door. Spray the lamp with your FLUDD to make a Blue Coin appear.
Blue Coin #21
On the third floor of the hotel, look on the ceiling to spot a large light. With your FLUDD, spray the center of the light to make a Blue Coin appear.
Blue Coin #22
On the third floor of the hotel, enter the room with the open door and hop on the bed to get to the attic. Once you’re up there, head to the far end and in the one bigger section, you will find some graffiti on the wall, so clean it for the coin.
Blue Coin #23
While you’re still in the attic, look for a single Boo enemy. Defeating it will make it drop another coin.
Blue Coin #24
Not far from Blue Coin #22, there will be a dead end that is housing this Blue Coin.
Blue Coin #25
When you first enter the attic from the bed in the open room, position the camera so that the Pianta cleaning is below you (overhead view). This will make it easier to point out directions to where you need to drop through the floor. First, you will want to head to the open section in the northwest corner, so Ground Pound the one tile here to drop into a room with a red Pianta, some glass in the center and a blank painting on the wall. Spray the blank painting to reveal a Shine symbol, with it coughing up a Blue Coin.
Blue Coin #26
From the previous coin, perform a Ground Pound on the glass in the middle of the room to end up in a room on the second floor. The bed there will probably bounce you back up, but there is another Blue Coin in plain view in this second floor room.
Blue Coin #27
Exit the door in the above room and return to the attic via the third floor open room, making sure to position the camera as pointed out before. Head to the northeast corner of the attic and go through the floor in that section. You will be in a room with some bookshelfs and a posted on the wall. Spray the one bookshelf next to the couch to get a Blue Coin.
Blue Coin #28
In the same room as #27, spray the poster on the wall to gain entrance to the next door room. There will be a Blue Coin in plain view here.
Blue Coin #29
Return to the same room as #27 and look for the discolored tile on the ground. Bust through it to enter a room on the second floor with some crates. Break open one of the crates by the doorway to find the Blue Coin.
Blue Coin #30
After acquiring #29, enter the adjacent room and you will find the Blue Coin in plain sight.