Is there any way to catch mew or mewtwo without restarting the g

Mewtwo is in Cerulean Cave. To get inside there, you need to beat the Elite Four.

Mew cannot be caught in the game, to my knowledge, with the exception of a glitch that I am not entirely sure about, although I do know it can cause your game to freeze. Mew can, or could only be obtained from Nintendo Events, but I don't think they host R/B/Y ones anymore.

You can get Mew through a glitch, but only if A) You have not faced the gambler outside of Underground Tunnel Near Lavender Town (he's directly south of the door) and B) You have not faced this one trainer near Bill's house that has a level 15 Slowpoke. You must go to the gambler, go right above him (right outside the door of Underground), and move one space down into his line of vision. Spam the start button so that battle is not initiated. Fly to Cerulean City. The guy will notice you, but then you will be taken away by Fly. You cannot open your menu for a time, so walk all the way up Nugget Bridge to the trainer with a slowpoke. Walk in a way so that he has to walk towards you in order to face you. Face him, then immediately fly to Lavender Town. Walk to the left back to the route where the gambler is. The game will freeze for a second, and then a level 5 Mew will appear (obviously, you can only do this glitch once, so save before the first step).

You don't need to restart the game to get Mewtwo. I actually caught another Mewtwo after I caught the original. What I did was I went to Cerulean Cave and then preformed the legendary Missingno. glitch. This is an easier way to get Mewtwo.

Hope I Helped
-1122andyozz33

If you beat the game you get to go into a cave near by where you live and capture Mewtwo. By beat the game I mean defeat the Elite Four and the Champion. Mew is only obtainable through a Pokemon Event, or using a Action Replay or GameShark.