World-crossing

"Blue Fairy: You will never make it to that world. Rumplestiltskin: Oh, I'll find a way. There must be other paths."

- The Blue Fairy and Rumplestiltskin World-crossing, also known as Portal Jumping in some cases, is a magical ability featured on ABC's Once Upon a Time and Once Upon a Time in Wonderland. It first appears in the first episode of the first season of Once Upon a Time.

Between Magical Worlds Only
Some methods are limited only to travel between magical worlds. However, travel to worlds without strong natural magic (such as the Land Without Magic) is possible if the location has strong magic (i.e. Storybrooke).
 * Black Fairy's limited ability (from the Dark Realm to a world and immediately back)
 * Cyclone (typically to Oz)
 * Darkness (from wherever to the Vault of the Dark One)
 * Divine Magic
 * Enchanted Mirrors (to the World Behind the Mirror and back)
 * Heroes and Villains book
 * Combined with Enchanted Quill
 * Combined with magic key
 * Genie's Wish
 * Jefferson's Hat (from a magical world to another and back)
 * The Hat's Looking Glass (to Wonderland and back)
 * The Hat's Fairy Tale Land portal
 * Door to the Land Without Color (to the Land Without Color and back)
 * Door to Victorian England (to Oz and back)
 * Oz Curtains Portal (to Oz and back)
 * Keys to the Land of Untold Stories (can turn any door into a portal to the Land of Untold Stories)
 * Kraken's Blood
 * Lake Nostos
 * Combined with dehydrated Magic Bean
 * Combined with Magic Wardrobe ashes + Enchanted Compass
 * Looking Glasses (to Wonderland, rarely back)
 * Mermaid Magic
 * Pegasus Sail (from Fairy Tale Land to Neverland and back)
 * Rabbit Holes
 * Savior Magic + Hrunting
 * Teleportation (rarely)
 * Time Travel Spell (from one time to another, and can cross worlds)

Between Magical and Non-Magical Worlds
Some methods can be accomplished regardless of whether the location is a magical world or a world without strong natural magic.
 * Apprentice's Portal Spell
 * Dark Curse (from wherever to Storybrooke and back if undone)
 * Magic Beans
 * Magic Doors
 * Magic Wardrobe
 * Shadow flight
 * Silver Slippers

Between the Afterlife and the Mortal Worlds
Some methods allow travel
 * Ale of Seonaidh (a soul from the Underworld to another world for a short period)
 * Fiery Cave (from the Underworld to a "Worse Place" or Mount Olympus)
 * Furies ability (from the Underworld to wherever and back)
 * Sleeping Curse (sends victim's soul to the Netherworld)
 * Summoning Ceremony (a soul from the Underworld to any world)
 * Underworld portal combined with blood of someone who has come back to life (to the Underworld or back)

Appearances
Note: "Archive" denotes archive footage.