Games like The Islander: Town Architect
Games like The Islander: Town Architect include Stardew Valley, Townscaper, SUMMERHOUSE, Farm Together, and Cities: Skylines II. We matched them by the tags players give The Islander: Town Architect on Steam (Casual, Indie, Building, Sandbox, and Pixel Graphics): closest matches first, and among equally close ones the better-known games.

Stardew Valley
Shared: Pixel Graphics · Relaxing · Sandbox

Townscaper
Shared: Building · Casual · Sandbox

SUMMERHOUSE
Shared: Casual · Sandbox · Building

Farm Together
Shared: Casual · Agriculture · Relaxing

Cities: Skylines II
Shared: Building · City Builder · Sandbox

Littlewood
Shared: Pixel Graphics · City Builder · Relaxing

Cities: Skylines
Shared: Building · City Builder · Sandbox

Garry's Mod
Shared: Sandbox · Building · Casual

Unpacking
Shared: Casual · Relaxing · Pixel Graphics

House Flipper
Shared: Building · Casual · Sandbox

People Playground
Shared: Sandbox · Building · Singleplayer

TheoTown
Shared: City Builder · Sandbox · Pixel Graphics

Tiny Glade
Shared: Building · Casual · Sandbox

Graveyard Keeper
Shared: Pixel Graphics · Sandbox · Indie

My Dream Setup
Shared: Building · Casual · Sandbox

DAVE THE DIVER
Shared: Casual · Pixel Graphics · Relaxing

Planet Coaster
Shared: Building · Sandbox · Simulation

Terraria
Shared: Sandbox · Pixel Graphics · Building

Two Point Museum
Shared: Casual · Building · Sandbox

Paralives
Shared: Building · Indie · Sandbox

Papers, Please
Shared: Indie · Pixel Graphics · Simulation

Potion Craft: Alchemist Simulator
Shared: Indie · Relaxing · Singleplayer

The Sims™ 4
Shared: Building · Sandbox · Casual

I Am Future: Cozy Apocalypse Survival
Shared: Casual · Singleplayer · Sandbox