|Full name||Unai Bustinza Martínez|
|Date of birth||2 February 1992|
|Place of birth||Bilbao, Spain|
|Height||1.75 m (5 ft 9 in)|
|Playing position||Right back|
|2015–2016||→ Leganés (loan)||15||(0)|
|* Senior club appearances and goals counted for the domestic league only and correct as of 14:15, 11 February 2019 (UTC)|
On 15 July 2014, Bustinza was promoted to the Basques' main squad in La Liga. He made his debut in the competition on 25 August, coming on as a late substitute in a 1–0 away win against UD Almería.
Bustinza was handed his first start for the Lions on 2 May 2015, in a 0–0 draw against Atlético Madrid, being sent off in the 93rd minute for two bookable offences. Late in the month, he played the full 90 minutes in the Copa del Rey final against FC Barcelona, a 1–3 loss.
On 22 July 2015, Bustinza was loaned to Segunda División club CD Leganés in a season-long deal. After achieving top level promotion, he signed a permanent three-year contract with the club on 18 July of the following year, after cutting ties with Athletic.
- Bustinza tendrá dorsal en el primer equipo del Athletic (Bustinza will have a jersey in Athletic's first team); Diario AS, 15 July 2014 (in Spanish)
- Etxeita da aire al Athletic (Etxeita gives air to Athletic); Marca, 25 October 2014 (in Spanish)
- El Atlético llega tarde (Atlético arrive late); Marca, 2 May 2015 (in Spanish)
- Messi es el Rey León (Messi is the Lion King); Marca, 30 May 2015 (in Spanish)
- Bustinza, cedido al Leganés (Bustinza, loaned to Leganés); Athletic Bilbao, 22 July 2015 (in Spanish)
- Bustinza vuelve al Leganés y firma hasta 2019 (Bustinza returns to Leganés and signs until 2019); CD Leganés, 18 July 2016 (in Spanish)