- Alex Devereaux – Mike Gagne
- Professor Matthew Alvarez – AJ Carter
- Special Agent Kerri Stone – Alex Jameson
- Dr. Donna Monroe – Stef Howerton
- Dr. Lynda Jacobs – Katie Sansoucy
- Lucas Miles – Graham Rowat
- BM1 Brown – Ronald Smith
- Alan Beasley – Zane Sexton
- Chief Herrick – Alicia Atkins
- Sector Boarding Team Member – Kae McSpadden
- Dig Site Security Guard – Karl Hynes
- Radio Voice – Mike Gagne
- Cultist – Erez Sarousi
- USCG District Commander – Scott Hart
- USCG Sector Commander – Kaitlin Kliman
- 911 Operator – Perky Perkins
- LT David Corbett – Sean Mish
- MK3 Mark Ashness – Boot McNally
- Micah Devereaux – Shayne Gardiner
- KEY LARGO Crewmember – Jen Gagne
- SN Jacques – Amy McNally
- LTJG Sacco – Ronny Cooke
- Boat Deck Supervisor – Boot McNally
- District 1 Command Center Watchstander – Lena Scott
- Sector Command Center Watchstander – Amy McNally
- Aircraft Commander – Leigh Gorrie
- Newscaster – Matt Raftis
- Operations Specialist Chief – Lorraine Hodgson
- CGIS Agent – Kae McSpadden
- Vanessa – Lena Scott
- BM3 Ramirez – Kaitlin Kliman
- Trevor (Injured college student) – Mike Gagne
- Ash Carlin – Ash Gagne
- BM2 Carter – Amanda Konstantin
- BM2 Reis – Lauren Amos
- Alex Devereaux – Mike Gagne
- Professor Matthew Alvarez – AJ Carter
- Special Agent Kerri Stone – Alex Jameson
- Dr. Donna Monroe – Stef Howerton
- Dr. Lynda Jacobs – Katie Sansoucy
- Lucas Miles – Graham Rowat
- BM1 Brown – Ronald Smith
- Alan Beasley – Zane Sexton
- Chief Herrick – Alicia Atkins
- Sector Boarding Team Member – Kae McSpadden
- Dig Site Security Guard – Karl Hynes
- Radio Voice – Mike Gagne
- Cultist – Erez Sarousi
- USCG District Commander – Scott Hart
- USCG Sector Commander – Kaitlin Kliman
- 911 Operator – Perky Perkins
- LT David Corbett – Sean Mish
- MK3 Mark Ashness – Boot McNally
- Micah Devereaux – Shayne Gardiner
- KEY LARGO Crewmember – Jen Gagne
- SN Jacques – Amy McNally
- LTJG Sacco – Ronny Cooke
- Boat Deck Supervisor – Boot McNally
- District 1 Command Center Watchstander – Lena Scott
- Sector Command Center Watchstander – Amy McNally
- Aircraft Commander – Leigh Gorrie
- Newscaster – Matt Raftis
- Operations Specialist Chief – Lorraine Hodgson
- CGIS Agent – Kae McSpadden
- Vanessa – Lena Scott
- BM3 Ramirez – Kaitlin Kliman
- Trevor (Injured college student) – Mike Gagne
- Ash Carlin – Ash Gagne
- BM2 Carter – Amanda Konstantin
- BM2 Reis – Lauren Amos
- Music courtesy of freemusicarchive.org and puple-planet.com
- Sounds effects courtesy of freesound.org and Adobe Audition
Boston Harbor Horror is a work of fiction. It is not endorsed by, or a reflection of, the U.S. Coast Guard, the Department of Homeland Security, or any agency or department of the U.S. Government.