Landorus is a special pokemon that you will only encounter once in Pokemon White.
After you get the National Pokedex, and once you have both Tornadus and Thundurus in your party (with one of them being caught in your game), head to the Abundant Shrine on Route 14. Click on the shrine, and as long as you have Tornadus and Thundurus in your party, Landorus will fly down and engage you.
You will need to trade for Tornadus, since you can only catch it in Pokemon Black.
Landorus is level 70 when you encounter it and has a low catch rate, so come prepared with high level pokemon and a lot of pokeballs.

blueexorcist1437 August 26, 2012 at 5:43 am
My Thundurus & Tornadus are traded. But I got a Landorus from trading, so I don’t really need to worry about catching him
Calum June 20, 2012 at 3:57 am
You can only catch it on pokemon white, I have a traded tornadus and a caught thunderus. I caught landorus ten minutes ago, worked fine. Thanks guys!
TheDizle (site admin) June 22, 2012 at 12:07 pm
You can catch Landorus in both versions.. Thundurus and Tornadus are the version specific ones.
daivik March 10, 2012 at 12:28 am
i have my thunderus and a traded or pokegen tornadus.Still saya a small weathered shrine. How do i get landorus to appear?
the dminator February 14, 2012 at 6:36 pm
Every time I try to catch thundorus on my pokemon white it says there’s an unusual thunderstorm on a route I go there and its not thunderstorming!!!!!!!!
Rose January 12, 2012 at 10:15 pm
Its not working, I have them both in my party i went to the shrine I clicked on it and all it says is “its a small weathered shrine”. Does it have to be your thundurus? Or someone else’s?
TheDizle (site admin) January 13, 2012 at 8:53 am
One of them has to be yours, whichever version comes from your game.
Jon June 15, 2011 at 9:35 pm
If both thunderus and tornadus are from a trade, can I release tornadus and re-catch him?
TheDizle June 16, 2011 at 11:15 am
I’m not sure how it works these pokemon received from trades, but in normal circumstances you just need to beat the Elite 4 to make legendary pokemon appear again.
TheDizle April 25, 2011 at 2:00 am
If you found this article helpful, please help me out and facebook it, tweet it, or stumble it, etc. with the links at the top. Thanks!