| Tropic Pool & Spa | Tropic Pool & Spa | — | (808) 822-7600 | Pool | Kapaʻa · Kauai County | — | — |
| Unlimited Construction Services Inc. | Unlimited Construction Services Inc. | — | (808) 241-1400 | GC, remodel, ADU | Lihue · Kauai County | — | — |
| Unrivaled INC | Unrivaled INC | info@unrivaled.com | — | Other | Lawai · Kauai County | — | — |
| Wasa Electrical Services INC | Wasa Electrical Services INC | — | (808) 245-2941 | Electricians | Lihue · Kauai County | — | — |
| Wave Security Of Kauai | Wave Security Of Kauai | — | (808) 639-4446 | Alarm and generators | Kauai · Kauai County | — | — |
| Waves Aquatics | Waves Aquatics | — | (808) 460-3474 | Pool | Kauai · Kauai County | — | — |
| Wet Paint Corporation | Wet Paint Corporation | online@wetpaint.com | — | Windows, patio, painters | Kapaa · Kauai County | — | — |
| Window Fashions Kauai Inc. | Window Fashions Kauai Inc. | — | (808) 634-3991 | Windows, patio, painters | Kapaʻa · Kauai County | — | — |
| Window Trends Of Kauai | Window Trends Of Kauai | kelly@windowtrends.com | (808) 332-9844 | Windows, patio, painters | Kalaheo · Kauai County | — | — |
| Window Works LLC | Window Works LLC | — | (808) 631-2618 | Windows, patio, painters | Kapaʻa · Kauai County | — | — |
| Windward Tree Service LLC | Windward Tree Service LLC | jay@windwardtreeservice.com | (808) 634-2717 | Tree | Kapaʻa · Kauai County | — | — |
| Xmx Power | Xmx Power | — | (808) 651-5886 | Electricians | Princeville · Kauai County | — | — |