English speaking skills are important in global communication and interaction. To speak English effectively at an acceptable level for a non-native speaker, various sub-skills are considered such as lexical resources, grammatical structures, pronunciation, rhythm, intonation, and the like. Nevertheless, a vast number of remote learners at Ho Chi Minh City Open University (HCMCOU) seemed to struggle in representing their thoughts and speaking sub-skills. Thus, this study aims to explore the challenges encountered by remote learners, the effectiveness of Project-Based Learning (PBL) applied in teaching speaking skills online, and learners’ attitudes towards the applied project. To do this, a mixed research method was employed. Twenty-two remote learners participated in responding to the survey questionnaire, and five of them were randomly selected for interview in depth. The finding shows that the most of remote learners had problems of speaking sub-skills, inadequate environments for speaking practice, communication, and interaction. Also, PBL is found as a unique method that enables learners to solve their existing problems, and improve their speaking skills, and all remote learners expressed their positive attitudes of towards PBL applied in their learning process.