What do I get on Southern Island in Emerald?

Whichever Eon Pokemon you didn't send roaming is sitting here, and it's holding a Soul Dew, the item that boosts both Latias and Latios and the only one you can get legitimately this whole generation. It's a level 50 catch, so come ready rather than expecting a pushover.

Do I have to trade for the second Lati in Emerald?

No trade required. Your mom's color question sends one Eon Pokemon roaming, and the Eon Ticket event drops the other onto Southern Island, so the two paths complete the pair on a single save. The real hurdle is the Eon Ticket itself, which only ever came from old giveaways.

Emerald Southern Island

A tiny event island reached with the Eon Ticket, where the Lati twin you chose back home waits beside the Soul Dew that sharpens its psychic power.

Southern Island is in Hoenn. In the story it comes after Faraway Island and before S.S. Tidal.

SOUTHERN ISLAND MAP

Emerald

Southern Island Walkthrough

0 trainers 1 item 0 species

After the game is clear, the harbor ferry sails to Southern Island only for a holder of the event ticket.

From the dock, follow the winding path north through the trees into the clearing.
Walk north up the middle of the clearing to the stone tablet at its center, and read it.
If Latias is the one roaming the region, Latios swoops down from the far end to battle you. If Latios roams instead, you battle Latias.
Catch it to take the Soul Dew it holds, because a knocked out one flies off for good.
Head south back to the dock and talk to the sailor to sail home on the ferry.

Legendary encounter

LatiosLv 50

Southern Island; requires Eon Ticket event item

Legendary encounter

LatiasLv 50

Southern Island; requires Eon Ticket event item

Soul Dew

Pokemon Encounters

✦Special encounters2

#380Latias

Legendary Lv 50

#381Latios

Legendary Lv 50

Legendary

#380

Latias

DragonPsychic

Level

EV yield

3 Sp. Def

Acquisition

Legendary

On Southern Island — requires the Eon Ticket event item

at Forest

Sealed locationForestSouthern IslandView on map

One-of-a-kind. You only get a single shot per cartridge — knock it out or run, and it is gone for the run. Save before engaging.

Latias page →

ITEMS

Southern Island holds a single treasure, the Soul Dew, which sharply boosts the Special stats of whichever Lati you catch.

Item ball1

Soul Dew

ITEM BALL

Soul Dew

Held by the Latias or Latios you meet here

Effect

Hold item: raises SP. ATK & SP. DEF of LATIOS & LATIAS.

Item ball1

Soul Dew

ITEM BALL

Soul Dew

Held by the Latias or Latios you meet here

Effect

Hold item: raises SP. ATK & SP. DEF of LATIOS & LATIAS.

Southern Island Guide

Whichever Eon Pokemon you didn't send roaming is sitting here, and it's holding a Soul Dew, the item that boosts both Latias and Latios and the only one you can get legitimately this whole generation. It's a level 50 catch, so come ready rather than expecting a pushover.
No trade required. Your mom's color question sends one Eon Pokemon roaming, and the Eon Ticket event drops the other onto Southern Island, so the two paths complete the pair on a single save. The real hurdle is the Eon Ticket itself, which only ever came from old giveaways.