David Thewlis

Sherlock Holmes

Blu Hunt

Amelia Rojas

Ardal O'Hanlon

Mr. Halligan

Mary O'Driscoll

Mrs. Halligan

Fiona Glascott

Lady Violet Somerset

Aidan McArdle

Chief Inspector Whitlock

Flynn Gray

Roberto Ricci

Doireann May White

Martha Ricci

Shane Lynch

Innkeeper

Kasper Andreasen

Cooper

Senan Jennings

Shrimpy

Hyoie O'Grady

Charlie Holroyd

Jamie Beamish

Constable Evans

Aisling Kearns

Cassie

Savonna Spracklin

Lucia Rojas

Paul Reid

Inspector Bullivant

Gia Hunter

Clara Anderson

Ivana Miličević

Marjorie Anderson

Phillip P. Keene

Paul Anderson

Bruno Gunn

Purser Curtis

Kojo Kamara

Clarence Halfpenny

Charlie Kranz

Pinkerton Detective

Bryan Quinn

Smales

Orén Kinlan

Shaw McPherson

Michael Gerwe

Gerald

Chris McHallem

Tomkins

Zahra Browne

Ruthie

Lalor Roddy

Colin

Michael Ellen Sean

Magott

Andy Kellegher

Weams

Joe Klocek

Dan Moriarty aka Michael Wylie

Dougray Scott

Professor Moriarty

Oliver Flitcroft

Constable Weaver

Caolan Byrne

Dankworth

Mark P. O'Connor

Arthur

Adam Behan

Coachman

Ian Dillon

Ballroom Guest (uncredited)

Seamus O'Hara

O'Leary

Jack Meade

Lord Withersea

Brendan Farrell

Coffin Fire Inspector

Antonio Aakeel

Detective Swann

Anthony Morris

Hackney Driver

Ruairí Heading

Pete Pound

Rose O'Neill

Emma

Shashi Rami

Bertram Birtwistle

Allan Keating

Mr. Hopper

Ben Waddell

Constable One

Jacinta Sweeney

Londoner (uncredited)