David starts at full-back just two weeks after impressing at the Singha Premiership Sevens while Scott is given the nod in the second row.
Warriors youngsters Beck Cutting and Nick Rigby are also named on the bench for England.
England Under 18 Head Coach John Fletcher said: “Everyone is going to get a start in the first two games, that is what we do on this tour and throughout the season. Everyone gets an opportunity to play.
“I’m pretty keen to get those guys that haven’t played before on the pitch and get them into games as fast as we can.”
England landed in Cape Town on Monday before travelling to their training base in Stellenbosch and the squad have been put through their paces ahead of Friday’s opener, having last played together in April.
England Under 18s:
Nick David (Worcester Warriors & Warwick), Arron Reed (Sale Sharks & Kirkham Grammar), Fraser Dingwall (Northampton Saints & Bedford School), Sam Spink (Wasps & Wellington College), Ollie Hassell-Collins (London Irish & St Pauls), Kieran Wilkinson (Sale Sharks & Kirkham Grammar), Will Porter (Wasps & Merchant Taylors), Sam Moore (Sale Sharks & Sedbergh School), Aaron Hinkley (Gloucester & St Peters), Tom Willis (Wasps & Henley College), James Scott (Worcester Warriors & Malvern College), Joe Tunney (Wasps & Dr Challoner’s), Joe Heyes (Leicester Tigers & Wyggeston & QEI College), Will Capon (Bristol & Bristol Grammar), Tom Rowland (Bristol & Bristol Grammar).
Replacements: George Head (Harlequins & Tonbridge School), Beck Cutting (Worcester Warriors & Bromsgrove), Nick Rigby (Worcester Warriors & Warwick), Josh Basham (London Irish & Wellington College), Richard Capstick (Exeter Chiefs & Exeter College), Ollie Fox (Yorkshire & New College Pontefract), Cameron Redpath (Sale Sharks & Sedbergh), Tom de Glanville (Bath & Beechen Cliff).
Fixtures:
Friday 11 August | England Under 18s v France | Paul Roos Gymnasium | Stellenbosch (1.15pm BST).
Tuesday 15 August | England Under 18s v Wales | Paarl Gymnasium | Paarl (1.15pm BST)
Saturday 19 August | England Under 18s v SA Schools | City Park | Athlone (1pm BST)