Summary: This dataset contains electroencephalographic recordings on 21 subjects doing a visual P300 experiment on PC (personal computer) and VR (virtual reality). The visual P300 is an event-related potential elicited by a visual stimulation, peaking 240-600 ms after stimulus onset. The experiment was designed in order to compare the use of a P300-based brain-computer interface on a PC and with a virtual reality headset, concerning the physiological, subjective and performance aspects. The brain-computer interface is based on electroencephalography (EEG). EEG data were recorded thanks to 16 electrodes. The virtual reality headset consisted of a passive head-mounted display, that is, a head-mounted display which does not include any electronics with the exception of a smartphone. A full description of the experiment is available at https://hal.archives-ouvertes.fr/hal-02078533. This experiment was carried out at GIPSA-lab (University of Grenoble Alpes, CNRS, Grenoble-INP) in 2018, and promoted by the IHMTEK Company (Interaction Homme-Machine Technologie). The study was approved by the Ethical Committee of the University of Grenoble Alpes (Comité d’Ethique pour la Recherche Non-Interventionnelle). Python code for manipulating the data is available at https://github.com/plcrodrigues/py.VR.EEG.2018-GIPSA. The ID of this dataset is VR.EEG.2018-GIPSA. Full description of the experiment and dataset: https://hal.archives-ouvertes.fr/hal-02078533 An analysis of the experiment: https://hal.archives-ouvertes.fr/hal-02464023 Principal Investigator: Eng. Grégoire Cattan Technical Supervisors: Eng. Anton Andreev, Eng. Pedro L. C. Rodrigues Scientific Supervisor: Dr. Marco Congedo ID of the dataset: VR.EEG.2018-GIPSA