Rule out the usual hiding places first. If the piece really is gone, check the set piece by piece
and leave with the element ID LEGO asks for, or a link to buy the part.
477 pieces in 137 part and color combinations, plus 4 minifigures.
The official piece count includes the 16 parts inside the set's minifigures, which this inventory lists separately. Spare parts are counted in neither figure.
Before you call it missing
Builders who report a missing piece often find it in one of these places. Tick each one off as you look.
Tile Special 2 x 2 InvertedRedPart 11203Element 6013868×1
Blue
6 pieces
Technic Pin Long with Friction Ridges Lengthwise, 1 Center SlotBluePart 42924Element 6299413×6
Coral
6 pieces
Equipment Hose Nozzle / Gun with Side String Hole SimplifiedCoralPart 60849Element 63224971 spare in the box×6
Dark Turquoise
5 pieces
Plate 1 x 2Dark TurquoisePart 3023Element 6213777 or 4218493×5
Light Bluish Gray
3 pieces
Plate Special 1 x 2 5.9mm Centre Side Towball SocketLight Bluish GrayPart 14704Element 6414561 or 6338165×1
Plate Special 1 x 2 5.9mm Towball SocketLight Bluish GrayPart 14418Element 6414556 or 6338163×2
Trans-Orange
3 pieces
Wave / Power Blast Rounded Energy with Bar HandleTrans-OrangePart 27393Element 6581318 or 6353240×3
Medium Azure
2 pieces
Plate 2 x 3Medium AzurePart 3021Element 6604733 or 6013828×2
Sand Green
2 pieces
Brick Curved Inverted 2 x 1Sand GreenPart 24201Element 6278553×1
Plate Special 1 x 1 with Clip Horizontal [Thick Open O Clip]Sand GreenPart 61252Element 6360112 or 6227077×1
Pearl Titanium
1 piece
Tile Special 1 x 2 with Sloped Walls AKA Money / Gold Bar [Ingot]Pearl TitaniumPart 99563Element 6208447×1
Trans-Clear
1 piece
Light Brick 2 x 3 x 1 1/3 with Dark Bluish Gray Base [Yellow LED]Trans-ClearPart 62930Element 6555880 or 6429472×1
[No Color/Any Color]
1 piece
Sticker Sheet for Set 76155-1[No Color/Any Color]Part 69942Element 6319546×1
Minifigures
4 figures
SersiMinifigure, checked as a whole figure×1
IkarisMinifigure, checked as a whole figure×1
KingoMinifigure, checked as a whole figure×1
AjakMinifigure, checked as a whole figure×1
Tick each piece as you find it, or mark it missing.
When a piece really is missing
Ask LEGO
LEGO takes requests for pieces missing from a new set through its customer service site. The form asks for
the set number and each piece's element ID, the number printed beside the piece in the parts list at the back
of the instructions. This checker lists both.
Mark a piece missing and your list links it to an eBay search for that part, which also covers pieces from
older or second-hand sets.
Keep a record
Copy or download your missing list (the CSV opens in any spreadsheet), or print the whole checklist and tick
pieces off on paper. Your marks stay in this browser, so you can check a big set over several sittings.