- Saint Anne (s) - White. Harrod.
- Sally Ann (s) - Rose pink. Brewer, 1998.
- Sally Unwin (s) - Rose pink.
- Salmon Beauty (e) - Spencer Praecox sweet pea with salmon flowers.
- Sandi Jones (s) - Dark pink. 2003.
- Sandringham (s) - Scarlet.
- Sarah (s) - Mauve.
- Sarah Kennedy (s) - Pale pink. Sewell, 2002.
- Sea Wolf (s) - A large flowered lavender flush sweet pea which quickly loses stem length.
- Second Honeymoon (s) - Lavender. Harrod, 2006.
- Selana (s) - Magenta.
- Senator (g) - Chocolate/purple bicolour stripe grandiflora sweet pea. Eckford, 1891.
- Sequoia (e) - Gold and salmon Spencer Praecox variety.
- Sheena (s) - Bicolour. 1993.
- Sheila Macqueen (s) - Salmon pink on cream ground.
- Shirley Pink (s) - Salmon pink on cream ground.
- Shirley Temple (e) - Spencer Praecox sweet pea with rose pink flowers.
- Sicilian Fuchsia (g) - Fuchsia standard with light pink wings from Peru. Aka Sicilian Pink. Harland, 1950s.
- Sicilian Pink (g) - Fuchsia standard with light pink wings from Peru. Aka Sicilian Fuchsia. Harland, 1950s.
- Silver Jubilee (s) - Orange-red. 1978.
- Silvia Simonetti (s) - Orange-red. Chisholm, 2006.
- Sir Cliff (s) - A rich rosy purple sweet pea, named in honour of popular singer Cliff Richard. 1999.
- Sir Jimmy Shand (s) - Mauve stripe on white. Chisholm, 2008.
- Sir Max Hastings (s) - Light maroon. Kerton, 2009.
- Snowdonia Park (s) - White. 1981.
- Snow White (s) - White. 1998.
- Snowlight (s) - White. Harrod.
- Solar Flare - Orange scarlet multiflora with dupex standard, not sunproof. Hammett, 2008.
- Solstice (e) - A series of day neutral early flowering sweet peas. Lemon.
- Solway Sunset (s) - Orange-cerise stripe. 2000.
- Sonia (s) - Pink with magenta veins. Hunt, 1985.
- Sophie (s) - Coral pink. Brackley, 1998.
- Sophisticated Lady (s) - light rose pink. Harrod.
- South Atlantic (s) - Lavender.
- South Pacific - A small flowered apricot sweet pea, not sunproof. Harrod.
- Southbourne (s) - A fine pale pink sweet pea. 1974.
- Southampton (s) - A frilly lavender sweet pea. 1978.
- Souvenir (s) - Lavender. 1996.
- Spaceman - Blue flush acacia leaf. Grayson, 1998.
- Spring Sunshine (e) - A series of early flowering cut flower sweet peas. Rowland.
- Stainless - Pale blue stained with dark blue flecks. Grayson, 1993.
- Starlight (s) - Carmine-magenta. Walker, 2004.
- Stella (e) - Cream EMG sweet pea.
- Steve Davis (s) - Cerise.
- Stithians (s) - Pale blue. 1994.
- Strawberry Fields (e) - An attractive fragrant coral/pink bicolour spring flowering sweet pea. Hammett.
- Strawberry Ice (g) - Pale magenta pink old fashioned type sweet pea. Parsons, 1998.
- Stylish (s) - An old mid blue sweet pea, now degenerate.
- Su Pollard (s) - Purple.
- Subtle Charm (s) - Pale pink. 1997.
- Sunset (s) - Salmon cerise. Unwin, 1972.
- Sunset (s) - Red. 1993.
- Sunset (s) - Raspberry blush. 2002.
- Sunsilk (s) - Orange-pink.
- Super Star (s) - Rose pink.
- Superfine (s) - A popular salmon pink sweet pea. Bolton, 1969.
- Susie (e) - Salmon cerise EMG variety.
- Susy Z (s) - A dramatic dark maroon 'flake' sweet pea. Rowland.
- Swan Lake (s) - An excellent pure white sweet pea in its day, now degenerate. 1950s.
- Sylvia (s) - Magenta.
- Sylvia Ann (s) - White. 1997.
- Sylvia Mary (s) - Orange-red.
- Sylvia Moore (s) - Rose pink on cream. 2000.