Bathymetric data was collected in June 2021 during the first marine expedition of the project "CRESCIBLUREEF – Grown in the blue: new technologies for knowledge and conservation" offshore Marzamemi village, Sicily, Italy (central coordinates of the investigated area are 36.73324N lat, 15.17894E lon, WGS85 – UTM 33N). Data were collected during a pole-mounted survey using a R2Sonic Multibeam Echosounder (MBES) combined with an integrated Inertial Navigation System (I2NS) and the Sound Velocity Sensor – Valeport miniSVS. The MBES was done onboard the minor vessel "Valerio" of Arena Sub S.r.l. over 45 tracks performed at an average speed of 5 knots in approximately three days of field work (22nd and 23rd of June, 2021). A total of about 17 km2 were investigated covering the depth range from about 15 to about 100 m. The final DTM was provided at 3x3m grid cell size.The dataset has been collected ruing a two days survey (First day Survey start: 2021-06-22T9:47:00 - Survey end: 2021-06-22T18:51:00; Second daySurvey start: 2021-06-23T9:31:00 - Survey end: 2021-06-23T18:26:00).Center location of the dataset is 36.73323537N; 15.17893943E.Sound velocity profile correction has been applied during processing by adding the SVP profiles collected during the survey into QPS Qimera software, which was used for the processing of all the MEBS data. In particular, a couple of sound velocity profiles were collected each working day, before starting the acquisition in the morning and in the afternoon, using a Sound Velocity Profiler – Valeport miniSVP. MEBS raw files data have been processed using QPS QImera software. Data was manually cleaned in order to remove noise spikes by using the swath/slice/3D editor. Navigation correction was not needed during data processing. Tide correction was not needed during processing because positional data was provided by a Trimble RTK GNSS receiver that was connected, in real-time, to a NTRIP network (Leica SmartNet ItalPoS). Thanks to the insertion of the specific geodetic reference and the GPS correction, the system was already corrected with the relative sea level position. Therefore, there was no need to apply a tide correction.