September is the turning point. After the relatively quiet summer, the autumn season begins — and with it the busiest buying period of the LEGO year. Three things define September: the August wave is finally broadly available at Dutch retailers, five advent calendars arrive on shelves, and LEGO Insider Days delivers the best offer LEGO.com has this quarter.
If you want to shop for Sinterklaas or Christmas without rushing and without out-of-stock risk, September is your month.
Practical planning: what should you do with this month?
Release months are tricky because every set briefly feels important. Split the list before prices start moving: sets you want to build immediately, and sets you only want at the right price. Buy the first group on availability; track the second group with a price alert.
| Moment | Action | Why |
|---|---|---|
| Before release | Make a shortlist of no more than three sets | It stops the whole wave feeling urgent |
| First week | Check stock before price | Popular sets move on availability first |
| After 3-6 weeks | Set alerts at 10-15% under RRP | That is when retailer gaps usually start |
| Around promotion weeks | Compare against historical low | A promotion only matters if it beats the normal pattern |
My rule: buy on day one only if you genuinely want to build it in the first week or need it as a gift. Everything else can wait for the first measurable price move.
August wave now broadly available
Sets that sold out quickly or went on a waiting list at LEGO.com on 1 August come back into stock in September. Amazon.nl and Bol.com fully process their August stock in week 1–2 of September.
What that means per set type:
- Star Wars flagship: check Amazon.nl and Bol.com from early September. When LEGO.com is sold out, those retailers often still have stock.
- Icons modular: typically returns first to LEGO.com itself (resupply), then to other retailers.
- City and Friends August sets: immediately broadly available in week 1.
LEGO Insider Days: the best LEGO.com moment of the quarter
Insider Days (formerly Insider Weekend) is a 48-hour event exclusively for LEGO Insider members. What’s historically on offer:
- Increased point bonuses on all purchases (sometimes 2x or 3x normal points).
- Exclusive GWP items at specific spend thresholds.
- Early pre-order access on autumn sets launching in October.
The exact 2026 date isn’t confirmed at time of writing, but the pattern is stable: somewhere between 21 September and 5 October.
My approach to Insider Days: combine a planned large purchase (100–150+ euro) with the 48-hour window. Don’t buy randomly to accumulate points. The value is in the combination of GWP, point bonus and possible early access to an autumn set you already wanted.
Advent calendars: buy now, not in November
Five advent calendars appear at major retailers in September:
- 75456 Star Wars Advent Calendar (293 pieces): traditionally the fastest to sell out.
- 76340 Marvel Advent Calendar (317 pieces): larger set, also popular.
- 60510 City Advent Calendar (252 pieces): most reliably stocked, even after November.
- 42698 Friends Advent Calendar (211 pieces): good choice for ages 6–10.
- 43298 Disney Princess Advent Calendar (290 pieces): new for 2026, expected popularity high.
For Star Wars and Marvel: anyone waiting until November finds them sold out or at secondary market prices. Buy in September if you want them with certainty. See the LEGO advent calendar guide 2026 for a detailed comparison.
September announcements: preview of October
September is also the announcement month for what launches in October:
- Winter Village 2026: the set is typically presented in September via LEGO Newsroom, launching in week 1–2 of October.
- First Black Friday signals: LEGO.com and larger retailers begin signalling their Black Friday approach in week 3–4 of September.
- Retirement announcements: sets stopping on 1 January 2027 are officially announced in September–October. Check the retiring sets guide 2026.
What I’d do in September
Two concrete steps:
- Choose and buy your advent calendar now. Compare the five options in the advent calendar guide and decide. Waiting costs you choice and money later.
- Plan a big purchase around Insider Days. If you want a large set anyway (for yourself or as a Sinterklaas gift), wait for the 48-hour event for maximum Insider value.
Beyond those two: no urgency in September. The sharpest price drops come in November.
Price data based on historical patterns. Advent calendar availability and retail prices are shown live on the set pages above.
Sets from this guide
The LEGO sets mentioned in this article, with live price comparison.
Which advent calendar do you buy in September?
Five calendars, four buying goals — these are the picks that make the most difference per buyer type.
Advent Calendar 2026
The 75456 Star Wars calendar is the safest choice for the widest audience and the first to sell out — buy it in September, not November.
LEGO ǀ Marvel Advent Calendar 2026
At 317 pieces with recognisable Marvel characters, the 76340 is the strongest calendar as a gift for a teenager or adult fan.
LEGO ǀ Disney Princess Advent Calendar 2026
New for 2026 and expected to be popular — the 43298 Disney Princess calendar has the best visual value per day for a December windowsill.
LEGO Friends Advent Calendar 2026
The 42698 Friends calendar is the least scarce of the five, so if an early retailer discount appears anywhere it will be here — set an alert and grab it when it moves.
How do you get the most from Insider Days?
September comes down to two decisions: buy your advent calendar before it sells out, and plan a large purchase around the 48-hour Insider Days event.
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Early September
Pick your advent calendar now
Star Wars (75456) and Marvel (76340) sell out in November — buy them in the first two weeks of September for certainty.
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Insider Days
Bundle your big purchase
Combine a planned purchase of 100–150+ euro with the 48-hour event: point bonus, GWP and sometimes early pre-order access on an October release.
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Outside Insider Days
No urgency at RRP
Outside the Insider Days window there is little reason to pay RRP in September — the sharpest discounts come in November.
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August set going scarce
Check retailer resupply
Popular 1-August sets that sold out at LEGO.com return to Amazon.nl and Bol.com in weeks 1–2 of September — but not indefinitely.