You can watch the TV series "Dexter" on several streaming platforms:

• Netflix offers "Dexter" for streaming, including multiple seasons with full episode descriptions available

• Paramount+ streams "Dexter" and provides a free trial option to start watching

• Hulu also streams "Dexter," featuring the original Showtime series with a free trial for new subscribers

• Amazon Prime Video has "Dexter" available for streaming, requiring a Prime membership

• Additionally, you can watch it on fuboTV and The Roku Channel (with ads) as well as buy or rent episodes on Apple TV and Amazon Video

So, depending on your subscription preferences, you can watch "Dexter" on Netflix, Paramount+, Hulu, Amazon Prime Video, and other platforms legally.