He achieved most success in Romania, representing in the country Gaz Metan Mediaș, Pandurii Târgu Jiu, Viitorul Constanța and Voluntari.

[4][5] He moved back to Série C, signing with Metropolitano with whom in 2007 he went on a tournament in Austria where he was noticed by Romanian Liga II club, Gaz Metan Mediaș who decided to transfer him on a one-season loan by paying $80.000, being presented at the team with fellow Brazilians Cairo Lima and Grillo Edson.

[4][5][6][7][8] He made his Liga II debut in a 3–1 victory against CSM Reșița, helping the team earn promotion to the first league by the end of the season under the guidance of coach Cristian Pustai, Eric contributing with 10 goals scored, forming a successful trio in the offence with Claudiu Boaru and Ciprian Prodan.

[4][5][13][14] Overall in the 2010–11 season, with a personal record of 15 goals scored in 31 appearances, of which the last two were a brace in a 3–2 victory against CFR Cluj, Eric was the second top-goalscorer of the season with three behind Politehnica Timișoara's Ianis Zicu, which helped the team finish on the 7th place, that gained Gaz Metan's first ever qualification to the Europa League, due to Politehnica Timișoara, who finished 2nd in the league table, being relegated by the Romanian Football Federation for not fulfilling the licence conditions to play in European competitions or Liga I.

[2][9][16][17] Shortly afterwards he left Gaz Metan to go on a trial with Bundesliga side VfL Wolfsburg but was not offered a contract, so he moved to Ukraine, signing with Karpaty Lviv.

[39] On 12 January 2019, Eric de Oliveira returned at Viitorul Constanța, helping the team win the 2018–19 Cupa României by the end of the season, scoring in extra time the decisive goal of the 2–1 victory against Astra Giurgiu from the final.

[2][6][42] In January 2020 he signed with Voluntari where in a 2–0 win over Hermannstadt he scored from a penalty kick his 65th Liga I goal which made him the best foreign goalscorer of the competition, surpassing fellow Brazilian Wesley.

[6][43] One year later Eric left Voluntari and signed a six months contract for a fourth spell with Gaz Metan Mediaș, however this time he did not make a single appearance for the team because of an injury.

[52] After he ended his playing career, Eric de Oliveira settled in Romania, being very attached to the country, saying in an interview:"I am 50% Brazilian, 50% Romanian, actually Transylvanian.