the best way is to get faster pokmeon (faster then the entei and raikou) i recomend a high level raichu and a high level gengar
first pralyze the Pokemon using thunder wave in raichu then they are going to flee
the second time you hunt them doen have gengar in front of your party when the battle begins use the move mean look then the entei or raiku whont be abel to escape (note if you switch out gengar mean look whont work) with gengar make them go to red health and start throwing pokeballs (i recomend searching the legendary dogs at night because dusk balls are more effective at night)
after that, someone at the battle frontier will tell you about latias and latios. then, latias will start roaming kanto.
he roams the map after you beat the game
Using a master ball
You cannot catch Raikou in Pokemon Diamond and Pearl. To get Raikou in Pokemon Diamond and Pearl, you must trade for one from Pokemon HeartGold and SoulSilver where it can be caught or transferring from Pokemon FireRed and LeafGreen.
mewtow zapdos moltres articuno mew entei raikou suicune
after you catch a glimpse of entei, raikou, and suicune at the burned tower in ecruteak city, you can track entei and raikou using your map.
Ho-Oh Lugia Suicune Articuno Zapdos Moltres Mewtwo Kyogre Raikou Entei Latias
after that, someone at the battle frontier will tell you about latias and latios. then, latias will start roaming kanto.
yes, if you have entei raikou or suicune.
to catch suicune,mewtwo,raikou and entei
You can only catch it when steven talks to you in vermilion city when you try to get the doll for the copycat. You catch it the way you caught raikou and entei
You cannot catch Raikou in Pokemon Black. You have to transfer it from Diamond, Pearl, Platinum, Heartgold, or Soulsilver.
you can either evolve zoura that you got from trading the event celebi, or trade over entei, suicune, or raikou from Pokemon heartgold/soulsilver. you cant capture zourark in the wild
he roams the map after you beat the game
ho-oh, lugia, suicune, entei, raikou
Using a master ball
You cannot catch Raikou in Pokemon Diamond and Pearl. To get Raikou in Pokemon Diamond and Pearl, you must trade for one from Pokemon HeartGold and SoulSilver where it can be caught or transferring from Pokemon FireRed and LeafGreen.