Jurgen Klinsmann's USA enjoyed a 2-0 win over arch rivals Mexico in Columbus, while the Ticos progressed despite being held to a 1-1 draw in Jamaica - courtesy of the fact there was not a winner in the Honduras-Panama encounter.
Eddie Johnson capitalised on a mistake by Mexico goalkeeper Jesus Corona to put the Americans ahead against Mexico four minutes into the second half and, 11 minutes from time, Landon Donovan converted Mikkel Diskerud's cross to put the result beyond doubt.
Klinsmann's side could have stretched their advantage even further but captain Clint Dempsey sent a penalty wide in stoppage time.
In Kingston, Randall Brenes put Costa Rica ahead with a right-footed strike in the 73rd minute after a mix-up in the Jamaica defence.
Jermain Anderson put a slight dampener on the visiting fans' celebrations with a stoppage-time equaliser for the bottom-placed Reggae Boyz, but the point proved enough for Costa Rica to ensure their fourth World Cup appearance - following adventures in 1990, 2002 and 2006.
Costa Rica coach Jorge Luis Pinto was unable to hide happiness, telling reporters: "We have an extraordinary group. We'll start working towards the World Cup."
Midfielder Michael Barrantes added: "We are celebrating because we deserve this achievement. We've made a step towards the future. We qualified for the World Cup!"
The result that helped Costa Rica progress was a 2-2 draw between Honduras and Panama in Tegucigalpa.
Honduras twice took the lead, but Gabriel Torres' brace ensured the spoils were shared.
Carlo Costly put the hosts ahead in the 27th minute, only for Torres to equalise five minutes after the break.
Wilson Palacios restored Honduras' lead just after the hour mark with a fine run into the box followed by a shot which left goalkeeper Jaime Penedo helpless, but Torres again got his side back on level terms - this time with a stoppage-time goal from Blas Perez's corner.
Honduras stayed third in the standings on 11 points and in pole position for the final direct qualifying spot - three points ahead of Panama and Mexico with two rounds of games remaining.