| Cultivar Name | Plant Size | Leaf Color | Variegation | Var Color | Origin | Flower Color | Season | Source | Registered |
| 'Sea Gulf Stream' | Large | Yellow | - | - | TC Sport | Near-White | June | Zilis, Mark & Malloy, Alex | .1999 |
| 'Sea of Japan' | Large | Blue/Green | Streaked | White | Unknown | - | - | Unknown | --NR-- |
| 'Sea Queen' | Medium | Blue/Green | | | Unknown | | | Seaver, Mildred | --NR-- |
| 'Sea Waves' | Large | Light-Green | - | - | Unknown | Pale-Lavender | June into July | Seaver, Mildred & Walek, Kevin & The American Hosta Society | .2009 |
| 'Sea Yellow Surprise' | Medium | Yellow | | | Unknown | | | Seaver, Mildred | --NR-- |
| 'Sea Yellow Waves' | Small | Yellow | | | Unknown | | | Seaver, Mildred | --NR-- |
| 'Seaside Splendor' | Large | Blue/Green | Streaked | Yellow | Hybrid | Light-Purple | August | Tylinski, Stan | .2003 |
| 'Seasurf' | Giant | Blue/Green | - | - | Unknown | - | - | Moldovan, Steve | --NR-- |
| 'Shells At Sea' | Medium | Dark-Green | Marginal | White | Hybrid | - | - | Arett, Anne | .1980 |
| 'Sky Blue Waters' | Large | Blue/Green | Marginal | Yellow | Hybrid | Light-Purple | July into August | Elslager, Ed | .2005 |
| 'Snake Pit Falls' | - | Med-Green | - | - | Hybrid | - | August to September | Moore, Jeff | --NR-- |
| 'Snowy Lake' | Medium | Blue/Green | Marginal | White | Sport | Pale-Lavender | June | Heims, Dan | --NR-- |
| 'Spindrift' | Large | Dark-Green | Streaked | Yellow | Unknown | - | - | Lydell, Ransom | --NR-- |
| 'Still Waters' | Medium | Blue/Green | - | - | Hybrid | - | June | Ward, Dr Dick & Ward, Jane | .2010 |
| 'Stormy Lakes' | Large | Blue/Green | - | - | Hybrid | Pale-Lavender | June into July | Goodale, T. | .2009 |
| 'Stormy Seas' | Large | Dark-Green | - | - | Hybrid | Pale-Lavender | June into July | Zilis, Mark | .2004 |
| 'Surf's Up' (Terpening) | Large | Blue/Green | - | - | Unknown | - | - | Terpening, Kent | --NR-- |
| 'Surf's Up' (Zilis) | Medium | Yellow | - | - | TC Sport | Pale-Lavender | July into August | Zilis, Mark | .2009 |
| 'Susquehanna River' | Small | Med-Green | Marginal | White | Hybrid | - | - | Beilstein, Doug & Malloy, Alex | --NR-- |
| 'Sycamore Creek' | Large | Dark-Green | Streaked | White | Hybrid | - | - | Moore, Jeff | --NR-- |
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