As technology advances, it gives rise to various modes of child sexual abuse. Forms of sexual abuse of children through technology can be categorized into several categories, including obscenity, approaching for sexual purposes, sexual chat, sexual extortion, and online sexual harassment. The purpose of this study was to identify the factors causing the occurrence of cyber child grooming crimes against children as well as the modus operandi of perpetrators in cyber child grooming crimes against children. The empirical normative technique is a type of research used by the author. The primary data source in this study is interview data obtained directly at the Bantul Class IIB Detention Centre. This study employs sociological and legal approach methods such as conceptual approaches, statutory approaches, and case-based approaches. Interviews with cyber child grooming offenders and data analysis using qualitative data analysis are among the methods used to collect data. Factors causing criminals to commit cyber child grooming crimes are obtaining sexual perpetrator satisfaction, environmental influences and the perpetrator's mindset, a low level of knowledge and understanding of social media use, opportunity, and the economy. The modus operandi of cyber child grooming includes ease of accessibility, relationship building, manipulation, sexual content, and risk management. Prisoner institutions, such as detention centres or prisons, are expected to always provide personality coaching (such as daily recitations, Qur'an reading, ablution procedures, and proper prayers) and independence coaching (such as skills education programs and job guidance) to cyber child grooming offenders so that the perpetrators do not commit their crimes again in the future.