Is it possible to catch Rayquaza on Pokemon Soul Silver?
Yes it’s possible. After you beat Red at Mt Silver, get the National dex, and select one the three Kanto starters, you have to first get the Red orb from Mr.Pokemon. Then head to a cave at Route 47 which will be the Embedded Tower and Capture Groudon. After you’ve captured Groudon, you have to show Prof Oak Groudon and Kyogre (This Kyogre must be one from Heart Gold, you’ll have to find someone to trade with temporary to show Prof Oak). After you show Groudon and Kyogre, head to the same place that Groudon was and Rayquaza will be there.