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Retiring soonAges 6+

Cat Birthday Party & Tree House (42666)

Name: Cat Birthday Party & Tree House
Brand: LEGO
SKU: 42666

Prices last checked: 28 October 2026 at 08:10

LEGO.com4.9(4)Amazon4.8321 pieces · 5.3p each

Available From

Cheapest right now

£17.07€20.39

Amazon DE

Save £7.92

32% under £24.99 RRP

Go to Amazon DE

Delivery not known · priced in EUR, converted at the ECB rate of 23 Oct 2026

Its price range since we started watchingtoday is near the bottom

£15.39 lowest£25.00 highest

Also available

Amazon UK

Marketplace sellers only

Amazon FR

Not re-checked since 4 Oct 2026

€20.99

Argos

Not re-checked since 13 May 2026

£25.00

LEGO.comOfficial

Sets the RRP everything else is measured against

£24.99

Buy

It was £15.39 at Amazon UK in October. Checked 40 times over 283 days · average £19.02.

Building Instructions Brickset

Price Analysis

Lowest Price Ever

£15.39

at Amazon UK · Oct 2026

Average Price (12mo)

£19.02

Current vs Average

-19.1%

Below average

Price Trend

Rising

Last 30 days

Best Month to Buy

June

Value Score

10.0/10

Price-per-piece vs theme avg

The lowest price we've recorded for Cat Birthday Party & Tree House is £15.39 at Amazon UK in October 2026. The current price is 19.1% below the 12-month average of £19.02. Prices have been trending upward recently. Consider buying soon if you spot a deal. Historically, June tends to offer the best prices for this set.

Price History & Buying Verdict

VerdictBuy now

•This set is marked as retiring soon by LEGO — once production stops, prices on the secondary market typically rise significantly.
•It's currently 19.1% below the 12-month average price of £19.02 — a notably good window.
•Prices have been rising over the last 30 days, so locking in the current price could be wise.
•On price-per-piece, this is one of the better-value sets in the Friends range (value score 10.0/10 vs theme average).
•A recent price drop of about £3.35 was recorded in the last 30 days.

We've been tracking the price of LEGO Friends Cat Birthday Party & Tree House (321 pieces) for 283 days, recording 40 data points across LEGO.com and major UK retailers. Over that period the price has dropped 15 times below previous levels, with the lowest price ever recorded being £15.39 at Amazon UK in October 2026.

The 12-month average sale price for set 42666 works out to £19.02 — that's 23.9% below the LEGO RRP of £24.99. The highest price we recorded across our tracked retailers was £25.00, giving a range of about £9.61 between the cheapest and most expensive observation.

Amazon UK has run the most price drops on this set in the period we've tracked, making it the retailer most worth watching for short-term deals. Historically, June has produced the lowest average prices for Cat Birthday Party & Tree House, so if you're not in a hurry it's worth bookmarking the page closer to that window. Prices have been trending upward over the last 30 days, so the deals window may be closing.

Want to see how LEGO Cat Birthday Party & Tree House (set 42666) compares against other sets? Browse the best-value LEGO sets or check the full price-history tracker.

Description

Cat Birthday Party & Tree House (42666) is a LEGO Friends set with 321 pieces, with an RRP of £24.99. Prices have been rising recently, so acting sooner may be wise. With a value score of 10.0/10, this set offers excellent value compared to other Friends sets.

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.

Features

A building kit for cat-loving kids – This LEGO® Friends Cat Birthday Party & Tree House toy for girls and boys aged 6 and up comes with 2 minidolls and 5 cat figures for imaginative play
Cat tree-house toy – Kids can have lots of fun playing with the 5 cats on the cat tree house, which features a fish-shaped piñata with treats inside, a cat toy, cat grass and a water fountain
Create stories with the LEGO® Friends characters – This pretend-play set comes with Leo and Paisley minidolls, 5 cat figures, a buildable cat tree house and a buildable birthday cake scene
Cat-themed accessories – Kids can create endless fun stories using the accessories, which include a birthday cake with candle, gifts, banners, cat-shaped balloons, a birthdayhat and cat treats
A gift for kids who love cats – This animal toy set makes a great creative gift for girls, boys and cat-lovers aged 6 and up or for anyone who would love to build a cat-themed birthday scene
Online show – Inspire more creative-play ideas with other sets (sold separately) and the LEGO® Friends: The Next Chapter online show, where kids can get to know the characters of Heartlake City
Let’s tell a friendship story – The LEGO® Friends range of building sets lets kids explore different friendship moments, with lots of opportunities to create their own imaginative stories
Measurements – 321-piece set with a main model measuring over 7 in. (18 cm) high, 6 in. (16 cm) wide and 4 in. (10 cm) deep

Minifigures Included

2 figures

Minifigures in Cat Birthday Party & Tree House. One of them appears in other sets we track, which can be a cheaper way to get the same figure.

Paisley - Bright Light Yellow Top
4 parts
Also in 1 other set›
- Heartlake City Ice Cream Truck42644 · £17.99 RRP
Leo - Red Shirt
4 parts

Minifigure data from Rebrickable.

Frequently Asked Questions about Cat Birthday Party & Tree House

What is the best price for LEGO Cat Birthday Party & Tree House (Set 42666)?

LEGO Cat Birthday Party & Tree House (Set #42666) is currently priced at £24.99 on LEGO.com. We continuously monitor prices across multiple UK retailers to find you the best deals.

How many pieces are in LEGO set 42666?

LEGO Cat Birthday Party & Tree House (Set #42666) contains 321 pieces. At the best available price of £20.39, that works out to approximately 6.4p per piece.

What age is LEGO Cat Birthday Party & Tree House suitable for?

LEGO Cat Birthday Party & Tree House (Set #42666) is recommended for ages 6+. This set is part of the LEGO Friends theme. View all Friends sets and deals.

Where can I find the building instructions for LEGO Cat Birthday Party & Tree House?

You can download the official building instructions for LEGO Cat Birthday Party & Tree House (Set #42666) for free from LEGO.com. Download the building instructions here. The instructions are available as a PDF and can be viewed on any device.

Where can I buy LEGO Cat Birthday Party & Tree House in the UK?

LEGO Cat Birthday Party & Tree House (Set #42666) is available from 1 UK retailer including Amazon DE. Prices range from £17.07. It's also available directly from LEGO.com at £24.99.

What is the lowest price ever recorded for LEGO Cat Birthday Party & Tree House?

The lowest price we've recorded for LEGO Cat Birthday Party & Tree House (Set #42666) is £15.39 at Amazon UK in October 2026. That's 38% off the LEGO RRP of £24.99. Track the latest movements on our LEGO price history page.

Is LEGO Cat Birthday Party & Tree House being discontinued or retiring soon?

Yes — LEGO Cat Birthday Party & Tree House is flagged as retiring soon by LEGO. Once production ends and remaining stock sells through, prices on the secondary market typically climb well above RRP. If this set is on your list, the safest window is now while retailers still have stock. Browse our list of retiring LEGO sets to see what else is on the way out.

Is LEGO Cat Birthday Party & Tree House good value for money?

Comparing piece-count to price across the LEGO Friends theme, this set scores 10.0 / 10 for value. That works out to about 6.4p per piece. That puts Cat Birthday Party & Tree House in the top tier of Friends sets for raw build value — you're paying noticeably less per brick than the theme average. Compare against other contenders on our best-value LEGO sets page.