The Legend of the Blue Sea

Assistant Director

• 
  Kim Seung Ho

Composer

• 
  Yoshimata Ryo
• 
  Huang Sae Joon

Director

• 
  Jin Hyeok

Screenwriter

• 
  Park Ji Eun

Main Role

• 
  Jun Ji Hyun

  Sim Cheong / Se Hwa

  Main Role
• 
  Lee Min Ho

  Heo Joon Jae / Kim Dam Ryung

  Main Role

Support Role

• 
  Lee Hee Joon

  Cho Nam Du

  Support Role
• 
  Shin Won Ho

  Tae Oh

  Support Role
• 
  Park Ji Il

  Manager Nam

  Support Role
• 
  Shin Hae Sun

  Cha Shi A

  Support Role
• 
  Moon So Ri

  Ahn Jin Joo

  Support Role
• 
  Lee Ji Hoon

  Heo Chi Hyeon

  Support Role
• 
  Park Hae Soo

  Hong Dong Pyo

  Support Role
• 
  Hwang Shin Hye

  Kang Seo Hee

  Support Role
• 
  Sung Dong Il

  Ma Dae Yeong / Mister Yang

  Support Role
• 
  Na Young Hee

  Mo Yoo Ran

  Support Role
• 
  Park Jin Young

  Heo Joon Jae [Young]

  Support Role
• 
  Shin Eun Soo

  Se Hwa / Shim Chung [Young] (Ep. 3, 4 ,13)

  Support Role
• 
  Jeon Jin Seo

  Heo Joon Jae [Child]

  Support Role
• 
  Gal So Won

  Shim Chung [Child]

  Support Role
• 
  Hong Jin Kyung

  [Homeless woman and Chung's friend]

  Support Role
• 
  Choi Jung Woo

  Heo Il Joong

  Support Role
• 
  Shin Rin Ah

  Seo Yoon Ah

  Support Role
• 
  Shim Yi Young

  Moo Yoo Ran [Young]

  Support Role
• 
  Jung Moon Sung

  Heo Gil Joong [Young]

  Support Role
• 
  Oh Yeon Ah

  [Mr. Yang's fiance]

  Support Role
• 
  Lee Jae Won

  Cha Dong Shik [Jin Joo's Husband]

  Support Role
• 
  Park Myung Shin

  [Chief Nam's wife]

  Support Role
• 
  Sung Chang Hoon

  [Yang's man}

  Support Role
• 
  Kim Jae Il

  Yoo Shi Joon [Prosecutor]

  Support Role
• 
  Lee Ho Jae

  Psychologist Jin Kyung-Won / Fortune Teller [Past]

  Support Role

Guest Role

• 
  Krystal Jung

  Min Ji [Flight attendant]

  Guest Role
• 
  Cha Tae Hyun

  [Con man]

  Guest Role
• 
  Ahn Jae Hong

  Kim Bong Seok "Missionary Thomas"

  Guest Role
• 
  Choi Kwon

  [Gil Joon's secretary - Young]

  Guest Role
• 
  Kim Sung Ryung

  Jang Jin-ok (Ep. 1-3)

  Guest Role
• 
  Lee Chae Kyung

  Sister Shin (Ep. 2)

  Guest Role
• 
  Seo Beom Shik

  [Gangster] (Ep. 2)

  Guest Role
• 
  Kim Hye Yoon

  [Jang Jin Ok's daughter] (Ep. 3)

  Guest Role
• 
  Seo Dong Won

  [Aquarium manager] (Ep. 3-4)

  Guest Role
• 
  Seo In Sung

  [Boy bumps Sim Chung] (Ep. 3-4)

  Guest Role
• 
  Kim Kang Hyun

  [Police officer] (Ep. 5)

  Guest Role
• 
  Park Jin Joo

  [Nurse] (Ep. 6)

  Guest Role
• 
  Kim Byung Chun

  [Vice President of Hospital] (Ep. 6.)

  Guest Role
• 
  Kim Soo Jin

  [Kim Yae Eun's mother] (Ep. 6)

  Guest Role
• 
  Jo Jung Suk

  Yoo Jong Hoon [Merman] (Ep. 7-8)

  Guest Role
• 
  Jung Yoo Mi

  Kim Hee Jin (Ep. 8)

  Guest Role
• 
  Ko Kyu Pil

  Han Seong Tae (Ep. 9)

  Guest Role
• 
  Im Won Hee

  [Doctor] (Ep. 19)

  Guest Role
• 
  Kim Seul Gi

  [Mermaid] (Ep. 20)

  Guest Role
• 
  Kim Ji An

  Kang Seo Hee [Young]

  Guest Role
• 
  Kim Sun Young

  [Woman at sauna]

  Guest Role
• 
  Lee Su Ryeon

  [Personal Shopper]

  Guest Role
• 
  Gu Da Song

  [Curious student]

  Guest Role
• 
  Kim Oh Bok

  [ER doctor]

  Guest Role
• 
  Lee Yu Jin

  [Woman @ open-air bath]

  Guest Role
• 
  Kim Yoon Tae

  [Lawyer]

  Guest Role
• 
  Noh Yi Han

  Ma Dae Young [Child]

  Guest Role
• 
  Kang Ro Chae

  [Lead female character on TV]

  Guest Role
• 
  Kim Dae Hyun

  Su Ha

  Guest Role
• 
  Park Sook Myung

  [Resident]

  Guest Role
• 
  Oh Yoo Mi

  [Mother with baby]

  Guest Role
• 
  In Sung Ho Guest Role
• 
  Gi Yeon Ho Guest Role
• 
  Kim Tae Young Guest Role
• 
  Choo Soo Bin Guest Role
• 
  Myung Seok Geun Guest Role
• 
  Park Seung Joon

  [Kid in picture]

  Guest Role
• 
  Kook Joong Woong Guest Role
• 
  Choi Chan Ho Guest Role
• 
  Seo Jeong Woo

  [High school student]

  Guest Role
• 
  Kim Jung Seok

  [Police chief]

  Guest Role
• 
  Oh Jin Ha

  [Gisaeng]

  Guest Role
• 
  Kim Joo Ah

  [Aqua Planet mother]

  Guest Role
• 
  Jung Tak

  [Boy in photo] (Ep. 11)

  Guest Role

Unknown

• 
  Carson Allen

  Mermaid

  Unknown
• 
  Kim Ok Joo Unknown
• 
  Kang Du Hyun Unknown