Skip to content
Back of the Box Builds

Back of the Box Builds

LEGO Alternate Builds!

  • SETS
    • Adventurers
    • Aquazone
    • Belville
    • Building Set with People
    • Castle
    • Duplo
    • Fabuland
    • Harry Potter
    • Holiday and Event
    • LEGOLAND
    • Model Team
    • Pirates
    • Space
    • Star Wars
    • Technic
    • 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 3591 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

886 – Back C

January 25, 2024March 2, 2026 Master Builder

1630 – Back C

April 8, 2025April 8, 2025 Master Builder

6953 – Back C

January 24, 2024January 25, 2024 Master Builder

6059 – Back C

July 13, 2021July 13, 2021 Master Builder

565 – Back C

December 28, 2023July 11, 2024 Master Builder

775 – Back B

July 22, 2024July 22, 2024 Master Builder

EXPLORE MORE OFFICIAL SETS

7130: Snowspeeder
Episode IV/V/VI Medium Builds Official Sets Star Wars Star Wars Sets 

7130: Snowspeeder

June 28, 2022June 28, 2022 Master Builder

Year Released: 1999BricklinkInstructions

801: Gear Set
Gears Medium Builds Official Sets Universal Building Set 

801: Gear Set

December 17, 2025December 17, 2025 Master Builder
1968: {Unknown}
Classic Space Classic Space Sets Medium Builds Official Sets Space 

1968: {Unknown}

August 28, 2020September 13, 2023 Master Builder
1728 (6145): Crystal Crawler {with Aqua Playscape}
ABCs Aquanauts Aquazone Aquazone Sets Box Plus Official Sets Playscape/Play Stage Box Small Builds 

1728 (6145): Crystal Crawler {with Aqua Playscape}

August 1, 2023March 22, 2025 Master Builder
6454: Countdown Corner
Medium Builds Official Sets Space Port Town Town Sets 

6454: Countdown Corner

July 14, 2021July 14, 2021 Master Builder
7190: Millennium Falcon
Extra Large Builds Official Sets Star Wars Star Wars Sets 

7190: Millennium Falcon

November 14, 2019November 14, 2019 Master Builder
6980: Galaxy Commander
Classic Space Classic Space Sets Extra Large Builds Official Sets Space 

6980: Galaxy Commander

July 21, 2021July 21, 2021 Master Builder
7115: Gungan Patrol
Official Sets Small Builds Star Wars Star Wars Sets 

7115: Gungan Patrol

January 12, 2021January 12, 2021 Master Builder
6110: Solo Sub
Aquazone Aquazone Sets Hydronauts Official Sets Small Builds 

6110: Solo Sub

February 13, 2025February 13, 2025 Master Builder
6074: Black Falcon’s Fortress
Black Falcons Castle Castle Sets Daniel August Krentz Large Builds Official Sets 

6074: Black Falcon’s Fortress

October 14, 2021July 29, 2023 Master Builder
6266: Cannon Cove
Imperial Guards Official Sets Pirates Pirates I Pirates Sets Small Builds 

6266: Cannon Cove

December 27, 2021June 3, 2022 Master Builder
6613: Telephone Booth
Classic Town Official Sets Town Town Sets Traffic Very Small Builds 

6613: Telephone Booth

November 6, 2024November 6, 2024 Master Builder
6465: Space Port Jet
Official Sets Small Builds Space Port Town Town Sets 

6465: Space Port Jet

March 3, 2025March 3, 2025 Master Builder
6357: Stunt ‘Copter N’ Truck
Classic Town Medium Builds Official Sets Town Town Sets Traffic 

6357: Stunt ‘Copter N’ Truck

January 28, 2022January 28, 2022 Master Builder
6345: Aerial Acrobats
Airport Classic Town Large Builds Official Sets Town Town Sets 

6345: Aerial Acrobats

January 29, 2021September 15, 2022 Master Builder
6276: Eldorado Fortress
Box Story Daniel August Krentz Extra Large Builds Imperial Soldiers Niels Milan Pedersen Official Sets Pirates Pirates I Pirates Sets 

6276: Eldorado Fortress

January 28, 2022April 3, 2024 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
  • Belville
  • Building Set with People
  • Castle
  • Duplo
  • Fabuland
  • Harry Potter
  • Holiday and Event
  • LEGOLAND
  • Model Team
  • Pirates
  • Space
  • Star Wars
  • Technic
  • 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.