Cat Birthday Party & Tree House

Cat Birthday Party & Tree House (42666-1) is a set in the Friends theme, released in 2025. It has 313 pieces and 2 minifigures.

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Number:42666-1
Released:June 2025
Pieces:313
Box size:19.1 × 26.2 × 6.1 cm
Box weight:434 g
Theme:Friends

Box size and weight as measured by Brickset.

In numbers

Over the last 30 days the lowest shop price recorded for this set was 22.69 USD, taken from 30 days with a price on record.

Since 9/25/2026 the lowest shop price has fallen from 25.03 USD to 22.79 USD, by 9 % (based on 42 days with a price on record).

LEGO expects to retire this set in December 2026.

Product details

Number: 42666-1
Name: Cat Birthday Party & Tree House
Theme: Friends
Released: June 2025
Launched: June 2025
Retires: December 2026 (expected)
Pieces: 313
Minifigures: 2
RRP: ≈ 28.08 USD (39.99 CAD) (Canada)≈ 33.66 USD (29.99 EUR) (Germany)≈ 32.99 USD (24.99 GBP) (United Kingdom)29.99 USD (United States)
Price per piece: ≈ 0.090 USD (0.128 CAD) (Canada)≈ 0.108 USD (0.096 EUR) (Germany)≈ 0.105 USD (0.080 GBP) (United Kingdom)0.096 USD (United States)
Best price (30 days): 22.69 USD
Price per piece (best offer): 0.073 USD
Barcodes from shop data, not confirmed: EAN-13 5702017783758

≈ marks a price converted into this currency at the ECB reference rate of its own date — a reference indication, not a tradeable rate. The price as observed follows in brackets.

BrickLink market data

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Description from LEGO.com

A creative toy building set for cat-lovers

Read the full description

Discover a paw-some building kit for girls, boys and cat-lovers aged 6 and up. The LEGO® Friends Cat Birthday Party & Tree House (42666) toy comes with 2 minidolls, 5 cat figures and lots of accessories for imaginative play packed with sweet kitty moments. This fun toy sets the scene for Churro’s birthday party. 4 of Churro’s feline friends are here too, plus LEGO Friends characters Leo and Paisley. Explore the fun details, including birthday presents, banners and cat-shaped balloons. Kids will love guiding the pets around the cat tree house, where there’s a fish-shaped piñata, a cat toy, cat grass, a water fountain and litter box. Then it’s time for the cats to sit at the rotating table to enjoy Churro’s birthday cake. With so many ways to play with this animal playset, kids can tell a different friendship story every time. Discover more exciting creative toys (sold separately) in the LEGO Friends universe. This LEGO set comes with the LEGO Builder app for intuitive building.

Source: LEGO Shop Advertising

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Pricing

Best price ever≈ 22.69 USD (20.39 EUR) Advertising Sealed · gross · Joybuy (DE) · seen 10/29/2026

Current best offer≈ 22.79 USD (20.39 EUR) Advertising Sealed · gross · Joybuy (DE) · seen 11/3/2026

Price history

Lowest shop price now22.79 USD
Lowest ever 22.69 USD

Each day's lowest price among the shops' current offers, including VAT. A price in another currency is converted at the ECB reference rate of its day.

Monthly lows as a table

Month	Lowest price
November 2026	22.78 USD
October 2026	22.69 USD
September 2026	24.92 USD

≈ marks a price converted into this currency at the ECB reference rate of its own date — a reference indication, not a tradeable rate. The price as observed follows in brackets.

Price statistics by condition

Nobody has sold this set recently.

Sources idee+spiel: 45 · Hamleys: 40 · Proshop: 35 · Thalia: 30 · LEGO® Shop (BR): 29 · Coolblue: 27 · LEGO® Shop (US): 26 · Coolblue (NL): 24 · LEGO® Shop (FR): 24 · Coolblue (BE): 21 · LEGO® Shop (DE): 20 · Thalia (AT): 20 · LEGO® Shop (CZ): 19 · LEGO® Shop (GR): 19 · bücher.de: 19 · LEGO® Shop (AT): 18 · LEGO® Shop (CH): 18 · LEGO® Shop (HU): 18 · LEGO® Shop (IT): 17 · LEGO® Shop (PL): 17 · LEGO® Shop (RO): 17 · LEGO® Shop (SK): 17 · OTTO: 17 · Orell Füssli: 17 · LEGO® Shop (BE): 16 · LEGO® Shop (GB): 16 · LEGO® Shop (DK): 15 · LEGO® Shop (ES): 15 · LEGO® Shop (FI): 15 · LEGO® Shop (IE): 15 · LEGO® Shop (LU): 15 · LEGO® Shop (PT): 15 · LEGO® Shop (SE): 15 · LEGO® Shop (NL): 14 · LEGO® Shop (NO): 14 · Joybuy (DE): 11 · Joybuy (UK): 10 · Toy Street: 10 · Zatu Games: 10 · Joybuy (FR): 9 · Joybuy (NL): 2

Where these prices come from

On eBay

The cheapest eBay listings we saw in the last seven days. They are sellers' asking prices, so they are not in the shop price list or the best offer.

We have not seen a current eBay listing for this set.

Recommended retail price

What LEGO published as the recommended retail price, market by market, in that market's own currency. No market's price is ever derived from another's.

Canada ≈ 28.08 USD (39.99 CAD) unknown tax basis Available since 5/7/2025 — still on sale as far as we know.Recorded by BrickDb since 10/2/2026

Germany ≈ 33.66 USD (29.99 EUR) gross Available since 5/7/2025 — still on sale as far as we know.Recorded by BrickDb since 10/2/2026

United Kingdom ≈ 32.99 USD (24.99 GBP) gross Available since 5/7/2025 — still on sale as far as we know.Recorded by BrickDb since 10/2/2026

United States 29.99 USD net Available since 5/7/2025 — still on sale as far as we know.Recorded by BrickDb since 10/2/2026

≈ marks a price converted into this currency at the ECB reference rate of its own date — a reference indication, not a tradeable rate. The price as observed follows in brackets.

Building instructions

All building instructions for this set on LEGO.com

Parts in this set

163 inventory lines

Catalogue image of the part Sticker Sheet for Set 42666-1

Sticker Sheet for Set 42666-1 10113040· [No Color/Any Color]

×1

Catalogue image of the part Bar Holder with Clip

Bar Holder with Clip 11090· White

×2

Catalogue image of the part Plate Special 1 x 2 with Clip Horizontal on Side

Plate Special 1 x 2 with Clip Horizontal on Side 11476· White

×1

Catalogue image of the part Brick Curved 2 x 1 No Studs [1/2 Bow]

Brick Curved 2 x 1 No Studs [1/2 Bow] 11477· Bright Green

×2

Catalogue image of the part Animal, Cat, Sitting with Dark Brown Stripes, White Chest, Ears print

Animal, Cat, Sitting with Dark Brown Stripes, White Chest, Ears print 11602pr0010· Medium Brown

×1

Catalogue image of the part Headwear Accessory Bow with Heart, Long Ribbon and Pin

Headwear Accessory Bow with Heart, Long Ribbon and Pin 11618· Lavender

×1

Catalogue image of the part String with End Studs 11L Overall

String with End Studs 11L Overall 14226c11· Black

×1

Catalogue image of the part Brick Arch 1 x 5 x 4 [Continuous Bow, Raised Underside Cross Supports]

Brick Arch 1 x 5 x 4 [Continuous Bow, Raised Underside Cross Supports] 14395· Tan

×2

Catalogue image of the part Brick Arch 1 x 6 x 2 - Thin Top without Reinforced Underside [New Version]

Brick Arch 1 x 6 x 2 - Thin Top without Reinforced Underside [New Version] 15254· Medium Azure

×1

Catalogue image of the part Brick Round 2 x 2 Dome Bottom [Open Stud]

Brick Round 2 x 2 Dome Bottom [Open Stud] 15395· Bright Pink

×2

Catalogue image of the part Plate Special Round 1 x 2 Half Circle with Stud (Jumper)

Plate Special Round 1 x 2 Half Circle with Stud (Jumper) 1745· Blue

×1

Catalogue image of the part Tile Round 1 x 2 Half Circle

Tile Round 1 x 2 Half Circle 1748· Medium Azure

×2

Catalogue image of the part Brick Curved 1 x 3 x 2 Inverted [Inside Bow]

Brick Curved 1 x 3 x 2 Inverted [Inside Bow] 18653· Medium Azure

×2

Catalogue image of the part Plate Special Round 2 x 2 with Center Stud (Jumper Plate)

Plate Special Round 2 x 2 with Center Stud (Jumper Plate) 18674· Blue

×2

Plate Special Round 2 x 2 with Center Stud (Jumper Plate) 18674· Dark Pink

×4

Plate Special Round 2 x 2 with Center Stud (Jumper Plate) 18674· Bright Green

×3

2 minifigures

Minifigures in this set

Leo - Red Shirt, Yellow Shorts

/ fig-016290 /

No retail priceNo recent sales

Paisley - Bright Light Yellow Top, Medium Lavender Skirt

/ fig-015754 /

No retail priceNo recent sales

Same theme, piece count within 15 %

Similar sets

Cat Birthday Party & Tree House

In numbers

Product details

BrickLink market data

Description from LEGO.com

Can I build this?

Pricing

Price history

Latest price from each shop

On eBay

Recommended retail price

Building instructions

Parts in this set

Minifigures in this set

Leo - Red Shirt, Yellow Shorts

Paisley - Bright Light Yellow Top, Medium Lavender Skirt

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