Although the game has this feature so far I have never used it, which is a shame because there are quite inspiring island designs out there. I will leave some codes from some islands that I found interesting and that I will inventively visit, but also a site where it generates random codes to visit.
Makoi Island – 3258-5626-9286
Aika Island – 1182-7179-4326
Toaru Island – 7307-4315-1221
Hitokui Island – 4088-8875-3480
Langerhans Island – 3524-5098-3702
Oni Island – 0520-1175-1035
Utsusemi Island – 4687-2003-7348
Protein Island – 1100-0112-3506
Ibuki Island – 5692-0162-5220
Zawa Island – 2627-6716-4541
Ride-On Island – 5316-9407-3632
Silenthill Island – 0167-0836-7272
Random Dream Island Codes: Site