I know that you can get Groudon in Ultra Sun, but can you get Kyogre without trading? Is there another way?
Did you beat the game yet because if you didn't this'll be a spoiler.
You can go in the Ultra Worm Hole at the Altar of the Moone and go in the wormhole.You can get Kyogre early in this way.(For proof I got Groudon early this way)You have to go in a very flashy blue wormhole.You might find other legendaries but there's a chance Kyogre will be waiting there.Kyogre is a ULTRA MOON only legendary.
In August, you will be able get a kyogre in Ultra Sun from the legendary year event.