The LEGO Cat Birthday Party (42666) is a quick but satisfying build, clocking in at 321 pieces. Released in 2025 as part of the Friends Pets collection, it retails for $29.99. The set includes 2 minifigures, adding play and display value.
You're looking at $0.093 per piece, which holds up well against other Friends sets.
For the price point, the Cat Birthday Party delivers a clean Friends build that's easy to recommend.
Key Features
321 pieces — Quick, focused build that's fun without the time commitment
2 minifigures — Collectible characters from Friends
$0.093 per piece — Better value than the Friends average
Pets subtheme — A popular subcategory within Friends
From 2025 — Modern LEGO design and packaging quality
Investment Analysis
The LEGO Cat Birthday Party (42666) is set to retire this year, which puts it squarely in the sweet spot for investors. Retail availability is winding down, and aftermarket demand typically picks up from here.
Investment-wise, we'd call this one decent.
Here's what stands out:
The $0.093 price-per-piece is well below average — good sign for value retention
Bottom line: Friends sets that retire with this profile usually see meaningful appreciation. If you spot the Cat Birthday Party on sale, don't overthink it.
Theme Background
As a 2025 addition to Friends, part of the Pets subcollection, the Cat Birthday Party slots into the more affordable side of Friends. Friends is consistently one of the top-performing LEGO themes, and at $29.99 this set is priced accordingly. The $0.093 price-per-piece makes it one of the stronger values in Friends right now.
Collectors following Friends specifically should note the Pets subtheme — it's a category that tends to draw attention and hold value, especially as sets in this tier age out of production.
Why This Set Is Special
Part-out value 2.6x retail. The individual parts are worth $76.69 on BrickLink — 2.6x the $29.99 retail price. Exceptional part-out value.
Frequently Asked Questions
[{"q": "How many pieces are in the LEGO Cat Birthday Party (42666)?", "a": "The LEGO Cat Birthday Party (42666) contains 321 pieces, making it a smaller set."}, {"q": "What minifigures come with the LEGO Cat Birthday Party (42666)?", "a": "The LEGO Cat Birthday Party (42666) includes 2 minifigures. Minifigures are a key value driver for LEGO sets \u2014 exclusive or rare minifigures can appreciate significantly in value on their own, sometimes commanding high prices on the secondary market."}, {"q": "How much does the LEGO Cat Birthday Party (42666) cost?", "a": "The retail price (MSRP) for the LEGO Cat Birthday Party (42666) is $29.99 in the United States. Regional pricing is \u00a324.99 in the UK, CA$39.99 in Canada, \u20ac29.99 in Europe. This works out to $0.09 per piece. That places it in the top 25% of Friends sets for value \u2014 you get a lot of pieces for the price you pay."}, {"q": "Is the LEGO Cat Birthday Party (42666) a good investment?", "a": "The LEGO Cat Birthday Party (42666) shows moderate investment potential based on several factors. Key investment signals include: excellent price-per-piece value. Friends sets have historically been among the best-performing themes for post-retirement appreciation. As with any LEGO investment, buying at or below retail price maximizes potential returns. Use the BrickBucks price tracker to find the best entry point."}, {"q": "What age is the LEGO Cat Birthday Party (42666) suitable for?", "a": "The LEGO Cat Birthday Party (42666) is recommended for ages 6+. The build is designed to be approachable for younger builders while still providing an enjoyable experience."}, {"q": "How big is the LEGO Cat Birthday Party (42666)?", "a": "The LEGO Cat Birthday Party (42666) measures approximately 19.10cm \u00d7 26.20cm \u00d7 6.10cm (W\u00d7H\u00d7D) and weighs 0.43kg. It makes for a great display piece that won't take up too much shelf space."}, {"q": "When will the LEGO Cat Birthday Party (42666) retire?", "a": "The LEGO Cat Birthday Party (42666) is projected to retire around December 2026. Once a LEGO set retires, it is no longer produced or sold at retail. This typically causes prices to rise on the secondary market as supply decreases while collector demand remains. Check the retirement countdown on this page for the latest status."}, {"q": "Where can I buy the LEGO Cat Birthday Party (42666)?", "a": "The LEGO Cat Birthday Party (42666) is available from major retailers including Amazon, Walmart, Target, and LEGO.com. Use the BrickBucks deal tracker to find current discounts and the best price available right now."}]
