Internet has evolved significantly from its establishment and it proceeds to do so. In addition, the Internet has become a part of people’s daily life. With the increasing number of internet users and various things that can be achieved through the internet, social media is also experiencing developments. This goes the same with marketing concept, where now the traditional marketing is shifted to modern marketing where now many companies use social media for marketing. This is known as social media marketing. Companies do this to enhance their consumer’s purchase intention and simply to promote their products. There are opportunities and new challenges for companies striving to boost their customers' buying intention through social media marketing. Moreover, there must be many aspects that may influence consumer’s purchase intention, precisely Surabaya consumers. Thus, this research is intended to analyze and explore the effect of Social Media Marketing Activities to Purchase Intention with the mediation of Value Equity and Social Brand Engagement of Skincare Somethinc in Surabaya. The data collected from Google Form, hence, there are 222 qualified respondents who live in Surabaya. In addition, the sampling method for this research is purposive sampling and the collected data is analyzed through Structural Equation Modelling (SEM) with SmartPLS 3.0 as the tool.