Inside sea ice are impermeable layers that trap material as well as highly porous layers full of algae. These features can be smaller than a few centimetres but are important for understanding biogeochemical cycles in sea ice. Traditionally, sea-ice samples are collected from ice cores cut into sections. Drawbacks to this method include difficulty cutting sections smaller than a few centimetres thick and contamination of samples. Brines may also drain out and be lost, meaning that important environments in sea ice may be overlooked or misrepresented. To address this, we developed a sea-ice melt probe that bores into sea ice and collects high-resolution samples. The melt-probe’s capability was tested during February-March 2023 at Saroma-ko Lagoon, Japan. Experiments consisted of testing the effect of the melt-probe temperature, its high-resolution capability, and ability to be deployed on snow-covered sea ice. Complimentary laboratory-based experiments included testing how well the melt-probe delineates layers by introducing a layer of dye to artificial sea ice. This proof-of-concept study hopes to provide an alternative method of sampling sea ice with the ability to support new research into the fine-scale structure of sea ice, with applications spanning challenging fields of research such as trace metals, microplastics and gases.