Firn cores OH-7 and OH-11 were retrieved from Plateau Laclavere, a small ice cap on the northernmost end of the Antarctic Peninsula, at about 1130 m above sea level (a.s.l.). OH-7 was drilled in January 2014 to a depth of 15.31 m using a mechanical 9 cm diameter drilling device (Rufli auger). OH-11 was drilled in January 2015 to a depth of 20.44 m. Firn core LP-01 was recovered from Plateau Louis Phillipe, which is located approximately 40 km south of Plateau Laclavere, at about 1390 m a.s.l. The core was drilled in January 2016 to a depth of 21.38 m. Cores OH-11 and LP-01 were obtained using a portable solar-powered and electrically operated ice-core drill (Backpack Drill; icedrill.ch AG). Subsamples for stable water isotope analysis were obtained from the three cores at 5 cm resolution. Stable water isotope measurements of OH-7 and LP-01 were performed at the ISOLAB Stable Isotope Facility of the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) in Potsdam, Germany, in summer 2017 and autumn 2018, respectively, using cavity ring-down spectrometers L2130-i and L2140-i (Picarro Inc.) coupled to an auto-sampler (L2130-i: PAL HTC-xt, CTC Analytics AG; L2140-i: Picarro Autosampler, Picarro Inc.). Stable water isotope measurements of OH-11 were conducted at the Stable Isotope Laboratory of the Universidad Nacional Andrés Bello (UNAB) in Viña del Mar, Chile, in autumn 2015 with an off-axis integrated cavity output spectrometer (TLWIA 45EP; Los Gatos Research). The three cores have not been dated yet. The data has been used in combination with data on the stable water isotope composition of three other firn cores from the same study area (doi:10.1594/PANGAEA.871083; doi:10.1594/PANGAEA.939718) to identify common isotopic patterns and to investigate their spatial and temporal variability.