Skip to content
Back of the Box Builds

Back of the Box Builds

LEGO Alternate Builds!

  • SETS
    • Adventurers
    • Aquazone
    • Belville
    • BATMAN™
    • BIONICLE
    • Building Set with People
    • Castle
    • Duplo
    • Fabuland
    • Harry Potter
    • Holiday and Event
    • LEGOLAND
    • Model Team
    • Pirates
    • Space
    • Star Wars
    • Technic
    • Train
    • Town
    • Universal Building Set
    • Western
    • More Sets
    • Misc
  • USEFUL LINKS
    • Submit Instructions!
    • New Instructions
    • New Official Sets
    • New Alternate Builds
    • Minifigs
    • Very Small Builds
    • Small Builds
    • Medium Builds
    • Large Builds
    • Extra Large Builds
    • How BOTBB was Built
  • THIS IS AN INDEPENDENT SITE NOT AUTHORIZED OR SPONSORED BY THE LEGO GROUP
Alternate Builds Instructions Added Large Alt Build Large Builds Model Team Model Team Alternate Builds 

5521 – Back A

January 29, 2026March 4, 2026 Master Builder 4645 Views

From: 5521: Sea Jet
Name: TBD 1
Instructions: View PDF | Download .io File

Contributions

  1. Name, PDF and .io file submitted on January 29, 2026 by: livi
  • ← Space Skeletal Horse Concept
  • 5581 – Back A →

You May Also Like

6539 – Back E

October 26, 2026October 26, 2026 Master Builder

6872 – Back B

October 19, 2019April 21, 2026 Master Builder

5986 – Back C

October 29, 2019April 4, 2020 Master Builder

6046 – Back B

November 18, 2021November 18, 2021 Master Builder

5550 – Back A

February 9, 2026March 4, 2026 Master Builder

6677 – Back E

June 8, 2023June 8, 2023 Master Builder

EXPLORE MORE OFFICIAL SETS

6270: Forbidden Island
Box Story Medium Builds Niels Milan Pedersen Official Sets Pirates Pirates I Pirates Sets 

6270: Forbidden Island

April 4, 2022February 21, 2025 Master Builder

Year Released: 1989Designer: Niels Milan PedersenBricklinkInstructions The box reads, “THE ADVENTURES OF THE LEGOLAND® PIRATES OF THE SEA! FORBIDDEN ISLAND

4762: Rescue from the Merpeople
Goblet of Fire Harry Potter Harry Potter Sets Medium Builds Official Sets 

4762: Rescue from the Merpeople

May 16, 2023May 16, 2023 Master Builder
8369: Dirt Crusher RC (Yellow)
Official Sets Racers Radio Control Small Builds 

8369: Dirt Crusher RC (Yellow)

November 13, 2024November 13, 2024 Master Builder
6815: Hovertron
Exploriens Exploriens Sets Official Sets Space Very Small Builds 

6815: Hovertron

June 28, 2022June 28, 2022 Master Builder
6081: King’s Mountain Fortress
Castle Castle Sets Crusaders Daniel August Krentz Extra Large Builds Official Sets 

6081: King’s Mountain Fortress

June 30, 2022July 29, 2023 Master Builder
6669: Diesel Daredevil
Classic Town Official Sets Race Small Builds Town Town Sets 

6669: Diesel Daredevil

March 17, 2022March 17, 2022 Master Builder
2846: Indian Kayak
Indians Official Sets Very Small Builds Western Western Sets 

2846: Indian Kayak

October 10, 2023October 10, 2023 Master Builder
6769: Fort Legoredo
Extra Large Builds Jørn Thomsen Official Sets Western Western Sets 

6769: Fort Legoredo

November 10, 2019July 29, 2023 Master Builder
6590: Vacation Camper
Classic Town Official Sets Small Builds Town Town Sets Traffic 

6590: Vacation Camper

July 8, 2022July 8, 2022 Master Builder
1680: Hay Cart with Smugglers
Castle Castle Sets Forestmen Official Sets Small Builds 

1680: Hay Cart with Smugglers

August 12, 2024September 24, 2024 Master Builder
4593: Zero Hurricane & Red Blizzard
Drome Racers Official Sets Racers Small Builds 

4593: Zero Hurricane & Red Blizzard

January 27, 2025February 21, 2025 Master Builder
7783: The Batcave: The Penguin and Mr. Freeze’s Invasion
Batman I BATMAN™ BATMAN™ Sets Extra Large Builds Official Sets 

7783: The Batcave: The Penguin and Mr. Freeze’s Invasion

March 27, 2026March 27, 2026 Master Builder
6082: Fire Breathing Fortress
Castle Castle Sets Dragon Knights Large Builds Official Sets 

6082: Fire Breathing Fortress

January 13, 2022January 13, 2022 Master Builder
6988: Alpha Centauri Outpost
Blacktron II Blacktron II Sets Large Builds Official Sets 

6988: Alpha Centauri Outpost

October 24, 2019October 24, 2019 Master Builder
7144: Slave I
Episode IV/V/VI Medium Builds Official Sets Star Wars Star Wars Sets 

7144: Slave I

October 28, 2021October 28, 2021 Master Builder
1843 – Bottom
Bonus/Value Pack Alternate Builds Castle Castle Alternate Builds Instructions Added Official Sets Royal Knights Small Alt Build Small Builds Space Spyrius Spyrius Alternate Builds 

1843 – Bottom

January 22, 2021March 14, 2025 Master Builder

BOXES

INSTRUCTIONS

FAVORITES

MINIFIGS

About This Site

Logo
There were once pictures of additional LEGO® builds on the back of set boxes. Written on the boxes was typically something about the endless building possibilities, "Build any of these exciting models with this set!" There were no instructions for these alternate builds, until now.

Sets

  • Adventurers
  • Aquazone
  • BATMAN
  • Bionicle
  • Belville
  • Building Set with People
  • Castle
  • Duplo
  • Fabuland
  • Harry Potter
  • Holiday and Event
  • LEGOLAND
  • Model Team
  • Pirates
  • Space
  • Star Wars
  • Technic
  • Train
  • Town
  • Universal Building Set
  • Western
  • More Sets
  • Misc

Useful Links

  • Submit Instructions!
  • New Instructions
  • New Official Sets
  • New Alternate Builds
  • Minifigs
  • Very Small Builds (<35 pcs)
  • Small Builds (<100 pcs)
  • Medium Builds (<200 pcs)
  • Large Builds (<400 pcs)
  • Extra Large Builds (>400 pcs)
  • How BOTBB was Built

In Honor of 1526

The classic space set that never was.

Copyright © 2026 Back of the Box Builds. All rights reserved. LEGO® is a trademark of the LEGO Group of companies which does not sponsor, authorize, or endorse this site.