The 19-year-old, who was recently with eighth-tier side Bedford Town, had been on trial at the Essex club in recent weeks.
The youngster signs a one-year contract at the club, after featuring in three Colchester Under-21s fixtures last month.
Barnes is eligible to feature for Colchester against Northampton Town on Tuesday.
Restore Data
| Team | P | W | D | L | F | A | GD | PTS | |
| 1 | Walsall | 19 | 12 | 4 | 3 | 35 | 19 | 16 | 40 |
| 2 | Port Vale | 20 | 10 | 6 | 4 | 26 | 19 | 7 | 36 |
| 3 | Crewe AlexandraCrewe | 19 | 9 | 7 | 3 | 24 | 16 | 8 | 34 |
| 4 | AFC Wimbledon | 19 | 10 | 3 | 6 | 31 | 16 | 15 | 33 |
| 5 | Doncaster RoversDoncaster | 20 | 9 | 6 | 5 | 28 | 23 | 5 | 33 |
| 6 | Chesterfield | 20 | 8 | 7 | 5 | 35 | 23 | 12 | 31 |
| 7 | Grimsby Town | 20 | 10 | 1 | 9 | 27 | 30 | -3 | 31 |
| 8 | MK Dons | 18 | 9 | 3 | 6 | 30 | 20 | 10 | 30 |
| 9 | Gillingham | 19 | 9 | 2 | 8 | 20 | 16 | 4 | 29 |
| 10 | Bradford CityBradford | 19 | 7 | 7 | 5 | 24 | 19 | 5 | 28 |
| 11 | Notts County | 19 | 7 | 7 | 5 | 25 | 21 | 4 | 28 |
| 12 | Salford City | 19 | 7 | 6 | 6 | 20 | 19 | 1 | 27 |
| 13 | Cheltenham TownCheltenham | 20 | 7 | 5 | 8 | 27 | 28 | -1 | 26 |
| 14 | Bromley | 19 | 5 | 9 | 5 | 23 | 23 | 0 | 24 |
| 15 | Fleetwood TownFleetwood | 18 | 5 | 8 | 5 | 24 | 23 | 1 | 23 |
| 16 | BarrowBarrow | 19 | 6 | 5 | 8 | 18 | 18 | 0 | 23 |
| 17 | Newport CountyNewport | 19 | 6 | 5 | 8 | 21 | 28 | -7 | 23 |
| 18 | Colchester UnitedColchester | 19 | 4 | 10 | 5 | 23 | 22 | 1 | 22 |
| 19 | Tranmere RoversTranmere | 19 | 5 | 6 | 8 | 14 | 26 | -12 | 21 |
| 20 | Harrogate TownHarrogate | 20 | 6 | 3 | 11 | 17 | 30 | -13 | 21 |
| 21 | Accrington StanleyAccrington | 19 | 4 | 7 | 8 | 26 | 34 | -8 | 19 |
| 22 | Swindon TownSwindon | 20 | 3 | 7 | 10 | 23 | 34 | -11 | 16 |
| 23 | Morecambe | 20 | 3 | 5 | 12 | 19 | 36 | -17 | 14 |
| 24 | Carlisle UnitedCarlisle | 19 | 3 | 5 | 11 | 15 | 32 | -17 | 14 |
| > League Two Full Table | |||||||||
