Tom's Studio Marianas Fountain Pen Ink – featuring the packaging, bottle and a swatch on paper

Fountain Pen Ink - 14 Marianas

This deep blue ink reflects the ocean’s mystical depths.

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The finest British-made fountain pen ink suitable for all pens. Named for the deepest point of the ocean (the Mariana Trench) this deep blue ink reflects the ocean’s mystical depths.

Transform the way you create with an ink colour that sets you apart!

Most pens offer ink cartridges in a limited selection of colours. I want to change that by bringing you this range of beautifully rich and distinctive inks – with no need to dispose of or replace an empty cartridge.

These wonderfully free-flowing inks come in a number of beautiful and nuanced shades. They truly are a joy to write or create with!

  • Each bottle holds 50ml of this lovely ink, enough to keep you going for reams of writing, drawing, or doodling.
  • All our inks are water-based, acid-free, non-toxic, and vegan-friendly.
  • Each ink comes beautifully presented in a stunning bottle with an antique laid paper, gold-foiled label.

Our fountain pen ink is compatible with all Tom’s Studio Pens, including calligraphy (The Flourish, Carrot, and Bloom), fountain (The Studio and Studio Pocket), and fineliner (The Lumos and Lumos Mini).


Fountain pen inks are highly 'layerable', allowing you to build different intensities or colours by applying more or less ink on the paper. Please note that the colour on the label may not perfectly represent the colour achieved when using different pens or techniques.


Because the ink has such a concentrated colour, you can dilute it with a smidge of water (ideally distilled) to create watercolour-like washes and depth of colour.

We aim to process your order within 1-3 working days. Please note that this increases to 1-4 working days for orders that include any personalisation, such as engraving.

Shipping costs
Shipping costs are calculated at checkout.

Delivery times

  • UK: 1-2 business days
  • Europe: 3-5 business days
  • USA: 5-7 business days
  • Rest of world: 8-10 business days (duties may apply on delivery)

Please refer to our Delivery page for more information, and reach out to us at hello@tomsstudio.co.uk if you have any further questions.

BUY 3 tom's studio fountain pen inks - save 20%

 
Tom's Studio Deep Black Fountain Pen Ink – featuring the packaging, bottle and a swatch on paper

Fountain Pen Ink - 01 Deep Black

Classical doesn’t have to mean boring, the very deepest of blacks.

£14.95
 
Tom's Studio Mallard Fountain Pen Ink – featuring the packaging, bottle and a swatch on paper

Fountain Pen Ink - 07 Mallard

A deep blue-green, like the plumes of a mallard duck

£14.95
 
Tom's Studio Marianas Fountain Pen Ink – featuring the packaging, bottle and a swatch on paper

Fountain Pen Ink - 14 Marianas

This deep blue ink reflects the ocean’s mystical depths.

£14.95
 
Tom's Studio Juniper Fountain Pen Ink – featuring the packaging, bottle and a swatch on paper

Fountain Pen Ink - 12 Juniper

What better inspiration than the Juniper plant, with its delicious bounty of deep purple berries.

£14.95

Customer Reviews

Based on 199 reviews
93%
(186)
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H
Hilary E.W.

Lovely inks and fast professional mail order service

R
Ray N.
Lovely Deep Blue Ink

This ink flows well and is a gorgeous deep blue colour - very impressed

J
Jane M.

Love this

J
Jane M.

Love this colour

J
Jane M.

Fantastic. Love the different colours of ink you can get

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