Whatmore was born in Ceylon (now known as Sri Lanka) and was educated at Royal College, Colombo. He and his family migrated to Australia in 1962.Thereafter he lived in Mentone, a suburb of Melbourne and studied at Mentone Grammar School.

Whatmore made his first class debut in 1975–76 touring South Africa with a Derek Robins XI. He debuted for Victoria at the end of that summer and in the next season became an important part of the Victorian team, being appointed vice captain under Graham Yallop.

Whatmore's first century came against South Australia which he followed with one against New South Wales.

Whatmore started the 1978–79 domestic season slowly, but eventually found form and became one of the most successful batsman that season. He also had to captain Victoria when Yallop was absent due to test duty, and played a vital role in the state winning the Sheffield Shield that summer.

International career

A century against Queensland late in the season saw him selected in the Australian team to play Pakistan, replacing Peter Toohey.

Whatmore impressed in his first test, top scoring in Australia's first innings with 43. He had to open in the second innings when Graeme Wood was unfit but only scored 15.

Whatmore was picked in the Australian squad for the 1979 World Cup.

He was also selected in the side that toured India in 1979. Whatmore's main challenger for a position in the side appears to have been Graeme Wood. Illness to Rick Darling saw both selected – Whatmore scored 20 and 8.

Whatmore was dropped for the second test but 60 in a tour game saw him back in the team for the third test. Whatmore made 14 and 33, the latter Australia's top score in the second innings.

Whatmore's best test batting came in the fourth test, with scores of 77 and 54; the latter knock was especially crucial as it helped Australia escape with a draw.

"He hits the ball cleanly and effortlessly and he's a natural shot maker", said captain Kim Hughes. "He's got the makings of a really top player."^[17]

However, in the fifth test Whatmore made 4 and 4^[18] and in the 6th 6 and 0.^[19] When Whatmore returned to Australian the World Series Cricket players had been readmitted to first class cricket and Whatmore lost his test place. However, he remained in good form for Victoria, and helped them win another Sheffield Shield. He played one ODI for Australia in the 1979–80 summer,^[20] was 12th man for another^[21] and was selected in the initial 18 man squad to go to Pakistan in early 1980.^[22] (He did not end up going).

Later playing career

Whatmore suffered a dip in form in 1980–81 and 81-82 seasons and was dropped from the Sheffield Shield Squad at one stage.^[23] However he bounced back and enjoyed his best ever season in 1987–88, making 912 runs at an average of 50.