Hooker Hartley has led the Saints since 2009 and will be the second Saint to skipper an England side this summer after Dowson did so against the Barbarians. With Saracen David Strettle dropping out of the squad altogether, Foden moves back to the wing to accommodate Alex Goode - who earns his first Test start and a second cap.
With pride at stake, Lancaster has made a further five personnel changes, Danny Care taking Ben Youngs' number nine jersey while Alex Corbisiero, Tom Palmer, James Haskell and Thomas Waldrom all start in the pack.
Lancaster is keen to end the tour on a high, having suffered reverses in Durban and Johannesburg, and hopes momentum can be carried from the midweek 57-31 win over SA Northern Barbarians.
"The guys did the shirt proud in Potchefstroom on Tuesday and I have no doubt that the 22 involved on Saturday will rise to this final challenge as we look to end this almost 12-month season on a high."
South Africa have made three changes in their bid for a series whitewash. In come debutant Jacques Potgieter and Gio Aplon for the injured Willem Alberts and Pat Lambie, while Wynand Olivier deputises for Frans Steyn, who is getting married.
ENGLAND TEAM TO FACE SOUTH AFRICA
Third Test
Port Elizabeth, SA
Saturday, June 23rd, 2012
Kick off: 4pm BST
Live on Sky Sports HD
15 Alex Goode (Saracens)
14 Chris Ashton (Saracens)
13 Jonathan Joseph (London Irish)
12 Manusamoa Tuilagi (Leicester Tigers)
11 Ben Foden (Northampton Saints)
10 Toby Flood (Leicester Tigers)
9 Danny Care (Harlequins)
1 Alex Corbisiero (London Irish)
2 Dylan Hartley (Northampton Saints)(capt)
3 Dan Cole (Leicester Tigers)
4 Tom Palmer (Stade Francais)
5 Geoff Parling (Leicester Tigers)
6 Tom Johnson (Exeter Chiefs)
7 James Haskell (Otago Highlanders)
8 Thomas Waldrom (Leicester Tigers)
Replacements
16 Lee Mears (Bath Rugby)
17 Joe Marler (Harlequins)
18 Mouritz Botha (Saracens)
19 Phil Dowson (Northampton Saints)
20 Lee Dickson (Northampton Saints)
21 Owen Farrell (Saracens)
22 Brad Barritt (Saracens)
