Southern Sting

Between 2002 and 2007, Telfer made 39 senior appearances for Southern Sting in the National Bank Cup league. She was just 17 and still a schoolgirl when she was recruited by Robyn Broughton to join Sting.^{[3][4][5][13][15]} While playing for Sting, she a member of four premiership winning teams, helping them win titles in 2002, 2003, 2004 and 2007.^{[6][16][17][18][19]}

Southland NPC

In 2008, Telfer captained the Southland team that won the National Provincial Championships. They defeated Auckland Waitakere 56–46 to win their first title in 49 years. The team was coached by Natalie Avellino and also featured Julianna Naoupu.^{[20][21][22][23][24][25]}

Southern Steel

Between 2008 and 2018, Frew played for Southern Steel, initially in the ANZ Championship and later in the ANZ Premiership. In 2009 and 2010, Frew was Steel vice-captain. Ahead of the 2011 season, together with Liana Leota, she was named co-captain.^{[5][11][26][27]} However she missed the 2012 season due to pregnancy.^[13][28] In December 2014, Frew was again named Steel captain.^[29][30] On 5 June 2016, during a Round 10 match against Mainland Tactix, Frew made her 100th ANZ Championship appearance.^{[13][31][32][33][34]}

On 12 June 2017, Frew was one of six Steel players in a van when it was involved in a road traffic accident in Fendalton, Christchurch. Four of the players were injured, including Frew who received over 70 stitches and under went surgery.^{[4][35][36][37][38]} Frew defied the medical experts and within 16 days, she had recovered to captain the 2017 Southern Steel to their first ANZ Premiership title, defeating Central Pulse 69–53 in the grand final.^{[4][37][39][40]} She also captained Steel when they won the 2017 Netball New Zealand Super Club tournament. However during the final against Northern Mystics, she suffered an Achilles tendon rupture that later required surgery.^[4][41][42] Ahead of the 2018 season, Frew was confirmed as Steel captain for the fifth successive season.^{[38][43][44][45]}

In July 2018, Frew announced she would retire at the end of the Steel's 2018 campaign.^[46] On 8 August 2018, for the Elimination final against Mainland Tactix, the ILT Stadium Southland was temporarily re-named the Wendy Frew Stadium in her honour.^{[4][47][48][49][50]} Frew captained the 2018 Southern Steel to their second ANZ Premiership title, defeating Central Pulse 54–53 in the grand final. She subsequently confirmed her retirement by sharing her celebrations on Instagram, including a Kurt Baker–inspired picture, captioned "That's me. I'm out". Frew posed topless, with two strategically placed netballs, on the shoulders of Gina Crampton as she proudly lifted the ANZ Premiership trophy.^{[51][52][53][54]}

Ahead of the 2020 season, Frew joined Southern Steel as an assistant coach.^[55][56] In May 2021, Steel introduced the Wendy Frew Medal, to be awarded to the Steel player who demonstrates excellence, commitment and loyalty.^[8][57][58] In April 2022, Frew was included on a list of the 25 best players to feature in netball leagues in New Zealand since 1998.^[59][60]

New Zealand

Telfer was a member of the New Zealand under-21 team that won the 2005 World Youth Netball Championships.^[61][62] On 2 November 2008, Telfer made her one and only senior appearance for New Zealand, playing the last quarter of a test against Australia. Ruth Aitken included her in further squads throughout 2008–09. However this remained her only senior appearance, finding herself behind Laura Langman and Joline Henry when it came to selection.^{[4][63][64][65][66][67]} She was however a member of the New Zealand team that won the 2009 World Netball Series, playing in matches against Malawi, England and Samoa.^[68][69]