Tiennan Costley
Rugby player
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Tiennan Costley (Japanese: ティエナン・コストリー, romanized: Tienan Kosutorī; born 14 June 2000), nicknamed "Tama" in the Māori language (English: Boy),[1][6] is a professional rugby union player who plays as a flanker for the Kobe Steelers in the Japan Rugby League One (JRLO) and the Japan national team.
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Costley (centre) with Japan in 2026 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Born | 14 June 2000 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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| Height | 192 cm (6 ft 4 in)[2] | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Weight | 102 kg (225 lb; 16 st 1 lb)[2] | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| School | Westlake Boys High School | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| University | International Pacific University | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Rugby union career | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Early life
Costley was born in 2000 and raised in New Zealand. He was educated at Auckland's Westlake Boys High School, playing rugby at the school alongside future England player Chandler Cunningham-South.[7][8]
Career
Early career
In 2017, Costley had been named in the North Harbour U18s squad.[9]
After graduating from Westlake Boys High School in Auckland, Costley originally hoped to progress through New Zealand rugby and eventually play for the All Blacks,[6] with the first goal of making the Canterbury Academy,[6] one of New Zealand's top rugby academies. After missing out on the Canterbury Academy, he was offered a place at IPU Kanto Pacific University in Japan.[6] During a visit to the university with his mother, Costley was impressed by the facilities and welcoming environment.[6] Costley eventually they chose to move to Japan and continue his rugby career abroad.[6]
After arriving in Japan, Costley began playing in the lower-level university competition for IPU. He played a total of seven matches across 2020, 2021, and 2022,[10] captaining the team in his final year in their first ever appearance in the All-Japan University Rugby Championship,[11][12] the highest level of youth competition in Japanese schools.
Kobe Steelers
In January 2023, Costley, alongside Hayato Fukunishi, were announced as the latest signings for the Kobe Steelers.[13] At the time, the Steelers had been in the early stages of their 2022–23 season. By March, and nearing the end of the season, Costley had made his senior debut for the Steelers, after an injury to regular back rower Marcell Coetzee.[6]
The following season, Costley started as the number eight in Kobe's first ten games of the season, racking up four tries. Alongside Ardie Savea, Costley became one of the Steelers' top weapons in the back row,[14] excelling at the breakdown and consistently breaking opposition defensive lines.[15]
In 2024–25, Costley remained a regular starter, though his role became increasingly versatile. Similar to his responsibilities with the Japan national team,[16] he featured across all three back-row positions. While he was deployed most frequently on the blindside (No. 6) and openside (No. 7), he also made a solitary appearance at number eight.[16]
In 2025–26, Costley had become the Steeler's starting blindside flanker,[16] playing in the position in all but one of their games throughout their title-winning campaign. Costley played a significant defensive role for the Steelers, alongside Ardie Savea. Costley racked up 245 tackles, the second-best in the league, with a success rate of 86.6%, ranking him among the top ten in the league.[17] He was also one of the league leaders in carry metres, defenders beaten, post-contact metres, line breaks, as well as turnovers won.[18] Following the regular season, Costley won the "Best Tackler Award".[17] The Steelers went on to win the Japan Rugby League One title, defeating the Kubota Spears 22–13 at the Japan National Stadium in Tokyo.[19] At the post-season awards, Costley was named in the league's best XV alongside teammate Ardie Savea.[20]
International career
In January 2024, Costley was named in a Japan training camp by coach Eddie Jones.[21] In May, following the 2023–24 JRLO season, he was named in another training camp ahead of Japan's Tests in the June–July international window.[22] In June 2024, Costley was named in Japan's starting squad to play England at the National Stadium.[23] Costley made his Test debut on 22 June 2024. Japan lost 17–52.[24]
The following July, Costley played in one of the Japan XV's two matches against the Māori All Blacks,[25] coming off the bench in the 50th minute.[16] He made another Test cap for Japan against Georgia a week later, although played just 16 minutes.[16]
In August and September 2024, Costley, with two Test caps, was named in Japan's 35-man squad for the 2024 Pacific Nations Cup.[26] Costley played in all four of their matches,[16] although had been made a replacement for Amato Fakatava in the latter stage of the tournament after starting in their opening pool stage matches against the United States and Canada.[16] Japan lost the final to Fiji at Hanazono Rugby Stadium in Osaka.[27]
Despite not being in Japan's squad for their two-Tests against Wales, Costley was later named in their 37-man squad for the second edition of the Pacific Nations Cup.[28] Costley played less than twenty minutes a match in three Tests, and made a further two caps for Japan in the 2025 Autumn International window against Australia[29] and South Africa respectively.[30] In the latter match, Costley was reported to have been used as a "hybrid player", covering the wing position when he was substituted on.[30]
In July 2026, Costley played in all three of Japan's Nations Championship Tests,[16] which inlcuded an equal record win over Italy in the opening round.[31]
Career statistics
Club
| Club | Season | League | |||
|---|---|---|---|---|---|
| Division | Apps | Tries | Points | ||
| Kobe Steelers | 2022–23 | Japan Rugby League One | 5 | 0 | 0 |
| 2023–24 | 16 | 4 | 20 | ||
| 2024–25 | 18 | 3 | 15 | ||
| 2025–26 | 19 | 7 | 35 | ||
| Total | 58 | 14 | 70 | ||
International
Awards and honours
Notes
- Both Costley's club, the Kobe Steelers,[1] and the Japan Rugby Football Union (JRFU),[2] state that Costley was born in New Zealand. However, several sources state that his birthplace is Australia.[3][4][5]