Pokemon Cosmic Emerald Download (Latest Version)

Pokemon Cosmic Emerald

Pokemon Cosmic Emerald is a GBA Rom Hack by SkyVortex Based on Pokemon Emerald in English. And it is now available to download. It was last updated on 12/24/2019.

Download Pokemon Cosmic Emerald GBA Rom hack

Hack ofPokemon Emerald

Also, be sure to check out Pokemon Mystical Legends.


I originally released it at PHO (and more recently its successor, Silph Co.), and due to several requests, brought it to the PokéCommunity. I hope you like him!

I’ve been working on Pokemon Cosmic Emerald hack for a long time – in small phases since I started hacking ROMs a few years ago. I don’t remember exactly when (maybe 2010?).

It’s been interrupted several times due to life circumstances, and a few times I’ve even redid it from scratch to find and fix any glitches/bugs; I’ve spent most of my time figuring out what the most minimalistic/efficient ways to implement everything are. Now it’s finally here, and with the latest update almost all the features I had planned are built in!

A change log (which differs from this one) has been kept, recording each and every change (as well as the dates of edits, revisions, and future ideas) so that I can quickly and easily find the root cause of any errors that may occur. The choice of programs and their use have been carefully considered to avoid interference. I’m also trying to keep the base ROM’s save data structure intact so that regular Emerald’s saves remain “backward/forward” compatible (originally for testing scripts, graphics, etc.). That may change in the future, but that will be done in a separate branch of this project.


This is essentially a quality of life ROM hack that doesn’t alter the main storyline. It keeps all the features of the original Emerald but adds a few things to make Pokemon Cosmic Emerald more fulfilling and fun. Remember the days when you could fly to the moon after a certain number of rocket launches/weeks? Several such things are taken into account, although with some modifications/changes in the way they are done. There is a moderate increase in difficulty (not really big, more for experienced players), but there are rewards that make up for it.

Only a few features of the newer generation have been added as I wanted to bring the gameplay of this hack as close as possible to the pre-2007 scene while incorporating some functional improvements of the newer games. However, I may include some newer generation Pokemon as special appearances/events in the distant future. Apparently expanding the PokéDex could result in the game only needing its own exclusive saves, but I guess that’s fine as long as you don’t plan on using the saves from this hack with the regular Emerald (or vice versa I guess). ). You should also keep in mind that if I ever release an enhanced Dex version, it may not be compatible with the saves from the regular version of this hack. Still, I won’t stop updating the regular version and will continue to release it should that be the case. I would also try to find a way to make the original saves compatible with the new version.

Planned Features and Ideas

  • Wild double battles
    • I know the Emerald Battle Engine Upgrade has these and many other great features, but using it will still see major changes to the combat system that are getting a bit too modern for this particular hack. If anyone knows of another way to add this feature please let me know as it would make the game much more fun.
  • If the Unlimited Berry Planting feature finally works, that would be great.
    • Note: I played through the original Emerald with this feature and can confirm it works (I checked old clay soil areas over several weeks and the berry plants are still there). I think the new day/night system or PRNG changes in this hack just prevent it from working properly.
  • Will the Cave of Alterations become something more interesting one day?
  • Maybe some additional graphics updates
  • More music editing
    • More day/night based song changes
  • More time-based weather changes on maps
  • It should be possible to change Deoxys’ form via a regular overworld script.
    • There’s already a way to switch between Speed and Normal, but I’m not sure at the moment if that’s possible via script. As long as I don’t expand the dex, it may be that it’s only possible to switch between speed and normal form with a patch.
  • Consistent (but perhaps not complete) decapitalization of uppercase words and phrases
    • I’m saving this point for last to avoid possible complex errors while I work on things. Honestly, I’m not sure if I even want to implement this or not.

Known Bugs

  • PokéDex text shift error on “EXP on catching Pokémon” when leveling up
    • It’s a bit annoying, but definitely not serious or game-breaking. There is currently no solution to this problem that I can use properly, but if I do it should be a simple, easy fix.
  • A feature is implemented that is supposed to allow berries to replant indefinitely, but it is buggy. I have no idea why, and the game basically completely ignores it, so it might as well not be there. Unfortunately, it is also quite tedious to test this.
  • If Wally catches his Ralts early in the game, the battle background will automatically change to the time of day when he exits the Pokéball menu. Unfortunately I have no idea how to fix this. I’ve tried, but it will probably require a little more than just script commands.
  • Some overworld sprites were incorrect and needed replacing, but I think I’ve gotten a handle on them all now. If you find any more oddly placed sprites like this, please let me know so I can fix it as soon as possible. It’s not a game-breaking issue or anything, but it just looks bad.
    • 5/31/2018 – I just found out that you may or may not see a random Lapras sprite in the Lilycove PKMN Center. For some reason it appears there as one of the game’s dynamic sprites, and thus never showed up as Lapras in the map editor. I’m not sure how to fix this now other than removing the dynamic sprite from the map which might amount to removing the original function it was intended for (which I don’t want to do though) .
  • Apparently that’s not a problem with the Pokemon Cosmic Emerald hack itself, but: For those using a GBA emulator on the Playstation Portable, the game may be showing an incorrect day of the week. In my case, the day in the game was one day behind the day in reality. For example, if it was Tuesday in reality, the game would show Monday when I used the clock. But that doesn’t happen to me when I use VBA.
  • When entering the Route 111 desert from above, a cactus (new tiles) may appear glitched. This is harmless and will even fix itself once the map is updated, but I plan to fix it with the next game update.
  • When customizing the colors of the characters, the last used “primary color” changes the bag in the inventory to that color (and also affects some colors in the opening sequence), even if you use separate colors for May/Brendan. Until a suitable solution is found, you should first use the colors for the rival and then those for your own character.




  • SkyVortex