© 2017 American Physical Society. We report measurements of the de Haas-van Alphen effect in the layered heavy-fermion compound CePt2In7 in high magnetic fields up to 35 T. Above an angle-dependent threshold field, we observed several de Haas-van Alphen frequencies originating from almost ideally two-dimensional Fermi surfaces. The frequencies are similar to those previously observed to develop only above a much higher field of 45 T, where a clear anomaly was detected and proposed to originate from a change in the electronic structure [M. M. Altarawneh et al., Phys. Rev. B 83, 081103 (2011)PRBMDO1098-012110.1103/PhysRevB.83.081103]. Our experimental results are compared with band structure calculations performed for both CePt2In7 and LaPt2In7, and the comparison suggests localized f electrons in CePt2In7. This conclusion is further supported by comparing experimentally observed Fermi surfaces in CePt2In7 and PrPt2In7, which are found to be almost identical. The measured effective masses in CePt2In7 are only moderately enhanced above the bare electron mass m0, from 2m0 to 6m0.