How many pieces does the LEGO Cat Birthday Party & Tree House (42666-1) have?

The LEGO Cat Birthday Party & Tree House set (42666-1) contains 321 pieces. It was released in 2025 as part of the LEGO Friends theme.

How can I find missing parts for LEGO set 42666-1?

On BrickMissing you can check which parts from the LEGO Cat Birthday Party & Tree House (42666-1) you already own. Add your LEGO collection and we'll show exactly which of the 321 pieces you're missing and which you already have.

Can I build the LEGO Cat Birthday Party & Tree House with parts I already have?

Use BrickMissing's free parts checker to find out. Add LEGO sets you own to your collection and we'll cross-reference all 321 parts to show your buildability percentage and which specific pieces you still need.

What theme is the LEGO Cat Birthday Party & Tree House from?

The LEGO Cat Birthday Party & Tree House (42666-1) belongs to the LEGO Friends theme. You can browse all Friends sets on BrickMissing to find more sets from this theme.

Cat Birthday Party & Tree House - View 9

Cat Birthday Party & Tree House

42666-1 Friends 2025 321 parts 6.2% repair risk Intermediate

The LEGO Friends 42666 Cat Birthday Party & Tree House invites you to a festive celebration in Heartlake City. This 321-piece set brings LEGO Friends characters Leo and Paisley together with Churro, the birthday cat, and four additional feline friends for a grand event. Explore the multi-level cat tree house, complete with a fish-shaped piñata, a refreshing water fountain, cat grass, and a hidden litter box. Adorned with colorful birthday banners, presents, and cheerful cat-shaped balloons, the scene culminates around a rotating table where Churro’s special birthday cake awaits. This vibrant model offers many detailed components, from the intricate piñata design to the functional rotating dining area, ensuring a lively display.

View at LEGO.com € 29,99→ lego.com

Parts Inventory

🧱 321 parts

Part	Color	Qty	LEGO price each
Sticker Sheet for Set 42666-1 10113040	Unknown	1×	Check price → View
Bar Holder with Clip 11090	White	2×	€0,12 View at LEGO → View
Plate Special 1 x 2 with Clip Horizontal on Side 11476	White	1×	€0,15 View at LEGO → View
Slope Curved 2 x 1 No Studs [1/2 Bow] 11477	Bright Green	2×	€0,06 View at LEGO → View
Animal, Cat, Sitting with Dark Brown Stripes, White Chest, Ears print 11602pr0010	Medium Brown	1×	€2,17 View at LEGO → View
Headwear Accessory Bow with Heart, Long Ribbon and Pin 11618	Lavender	1×	€0,08 View at LEGO → View
String with End Studs 11L Overall 14226c11	Black	1×	€1,96 View at LEGO → View
Brick Arch 1 x 5 x 4 [Continuous Bow, Raised Underside Cross Supports] 14395	Tan	2×	€0,28 View at LEGO → View
Brick Arch 1 x 6 x 2 - Thin Top without Reinforced Underside [New Version] 15254	Medium Azure	1×	€0,27 View at LEGO → View
Brick Round 2 x 2 Dome Bottom [Open Stud] 15395	Bright Pink	2×	€0,17 View at LEGO → View
Plate Round 1 x 2 Half Circle with Stud (Jumper) 1745	Black	1×	€0,15 View at LEGO → View
Tile Round 1 x 2 Half Circle 1748	Medium Azure	2×	€0,13 View at LEGO → View

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Repairability

Can you fix Cat Birthday Party & Tree House if a piece goes missing?

6.2%Moderate repair risk

easy to fixguard this box

9 of the 146 part+color combinations in this set appear in 3 or fewer sets ever made. Lose one of those and a replacement is very hard to find.

Theme average

6.2%

All sets

6.7%

Hardest to replace

Sticker Sheet for Set 42666-1 · Unknown · only this setBrick Curved 2 x 1 · Coral · only this setBuy at LEGO ↗ Minidoll Torso Boy · Medium Nougat · 2 sets ever

How we calculate this →