InPada themusim summer ofpanas 1991, penampilan Costa'sdisplays atdi Fafe hadsangat mengesankan impressedpelatih Portugal UnderU-21 coach [[Carlos Queiroz]] sosehingga muchdia thatdipanggil heke wastim calleduntuk up to the team to representmewakili Portugal in thedi World Youth Cup. TheTim Portuguesenasional underU-20 nationalPortugal team won a [[FIFA U-20memenangkan World Cup|World Youth Championship]]inpada tahun 1991. HisTendangan clinchingpenalti penaltymelawan kickBrasil against Brazil in thedi final helpedmembantu winmemenangkan thegelar titledi onkandang homesendiri soildan and announcedmengumumkan Costa assebagai onesalah ofsatu theanggota brightestpaling memberscemerlang ofdari whatapa wouldyang becomekemudian knowndikenal as thesebagai "GoldenGenerasi GenerationEmas.”"
Costa wasadalah aanggota memberdari oftahun-tahun Portugal'spaling mostkonsisten consistentPortugal yearsdi atlevel senior levelsaat astim themencapai teamperempat reachedfinal the quarter-finals of [[UEFA Euro 1996]] , the semi-finals of [[UEFAsemifinal Euro 2000|Euro2000]]dan and the [[UEFA Euro 2004 Final|final of UEFA Euro 2004]].
Costa sangat berperan dalam membantu Portugal mencapai final 2004 di kandang sendiri, mencetak gol di Estádio da Luz melawan Inggris di pertandingan perempat final, dan melihat Costa yang putus asa di akhir pertandingan 1-0 kekalahan dari Yunani adalah salah satu gambaran abadi dari turnamen tersebut
Costa was especially instrumental in helping Portugal reach the 2004 final on home soil, scoring a screamer of a goal at the Estádio da Luz against [[England national football team|England]] in the quarter-final match, and the sight of a distraught Costa at the end of a 1–0 defeat to [[Greece national football team|Greece]] was one of the enduring images of the tournament.
Costa juga ambil bagian dalam Piala Dunia FIFA 2002 di Jepang dan Korea Selatan, mencetak gol kemenangan [[Tim nasional sepak bola Portugal|Portugal]] dalam kemenangan 4-0 mereka atas [[Tim nasional sepak bola Polandia|Polandia]]. Satu-satunya saat dalam karirnya Costa dikeluarkan dari lapangan adalah dalam pertandingan internasional melawan [[Tim nasional sepak bola Jerman|Jerman]].
Costa also took part in the [[2002 FIFA World Cup]] in Japan and South Korea, scoring Portugal's winning goal in their 4–0 win over [[Poland national football team|Poland]]. The only time in his career that Costa was sent off was in an international game against [[Germany national football team|Germany]].
DespiteMeski beingpada principallydasarnya amenjadi providerpenyedia, Costa scoredmencetak 26 goalsgol indalam 94 gamespertandingan; hedia isadalah Portugal'spemain eighth-highestdengan caps tertinggi kedelapan Portugal cappeddan playerpencetak andgol seventh-highesttertinggi goalscorerketujuh.<ref name="Portugal - Record International Players">{{cite web|title=Portugal – Record International Players|url=https://www.rsssf.org/miscellaneous/port-recintlp.html|publisher=Rec.Sport.Soccer Statistics Foundation|access-date=24 July 2015}}</ref>
