Early career teachers (ECTs) face numerous challenges during their transition from preparation programmes into professional employment contexts. Social media platforms have created many new opportunities for teachers' ongoing professional learning by putting them in contact with other teachers from anywhere in the world. However, being connected to more people also means that ECTs must navigate an increased number of potentially conflicting messages about what and how to teach. Thus, entering the profession presents ECTs external conflicts as they adjust to new colleagues and internal conflicts as they encounter cognitive dissonance between old and new ideas. This study explores how and why ECTs expand "professional learning networks" (PLNs) - that is, the supports, people and spaces useful for improving teaching and learning - with social media in response to early career challenges. Interviews with nine ECTs demonstrate that they expand PLNs to navigate change, scarcity of resources and conflicting teaching beliefs. Interviewees use social media to look for supports for instructional practise and for connecting socially, but they also described how they maintain boundaries around their social media use. Implications are discussed for ECTs, administrators and education leaders - especially regarding how stakeholders can help alleviate early career pressures on ECTs.