Canvey fought back from two goals down before letting a lead slip themselves.
The visitors went ahead when Neil Ross headed home Tristram Whitman's cross and Lee Colkin curled in a superb second to put the Lambs in control.
John Keeling pulled one back just before the interval when he collected Lee Boylan's pass and netted.
Boylan levelled matters from the spot and he scored his second of the game 11 minutes later, only for Whitman to level, before Keeling was sent off.
Canvey Island: Potter, Chenery, McGhee, Smith, Kennedy,
Minton (Gooden 21), Keeling, Sedgemore, Duffy (Joseph 89),
Gregory (McDougald 88), Boylan.
Subs Not Used: Cowan, Harrison.
Sent Off: Keeling (90).
Booked: Gregory, Kennedy, Keeling, Gooden.
Goals: Keeling 44, Boylan 55 pen, 65.
Tamworth: Price, Adie Smith, Redmile, Brown, Stamps, Colkin,
Ebdon (Bampton 62), Blunt (Sheppard 14), Cooper, Ross (May 68),
Subs Not Used: Turner, Shaw.
Booked: Sheppard, Adie Smith, Redmile.
Goals: Ross 23, Colkin 35, Whitman 71.
Ref: G Evetts (Hertfordshire).