Journalist Pablo Oliveira first reported the interest from both Spanish clubs in the 22-year-old, who has scored five goals and provided one assist in 22 appearances for Botafogo in 2026.
Celta, who secured Europa League qualification on the final day of the LaLiga season, and Betis, who return to the Champions League for the first time in over 20 years, are both looking to strengthen their wide attacking options this summer.
Martins joined Botafogo from Udinese in July 2024 for €10 million, but the Rio de Janeiro club are under significant financial strain. They owe Udinese a reported €6 million from that transfer — a dispute referred to FIFA — and are actively looking to sell assets to ease their situation. His contract runs until December 2028.
Betis's Champions League qualification gives them a significant advantage in the pursuit. Celta, who previously identified and signed other young South American talents at reduced valuations during moments of institutional instability at their selling clubs, are experienced in exactly this type of operation.
Coventry City, Feyenoord and Krasnodar are also credited with interest. Coventry's interest is notable given the English club's first Premier League season in 25 years under Frank Lampard, though the competition from European football clubs gives the Spanish sides an inherent edge.
Martins spent the 2023-24 season on loan at Watford, making 49 Championship appearances and scoring six goals. He has English football experience that several Premier League-linked clubs consider a practical advantage.
Whether Botafogo's asking price holds firm at €8 million or softens further as the window progresses will likely determine how quickly this moves. The financial pressure on the seller points toward the latter.