This study examined whether English literacy instruction given to Japanese second-grade elementary school students facilitated the development of their phonemic awareness. Two research questions were set: (1) Can synthetic phonics instruction improve the phonemic awareness of elementary school students? and (2) Are there differences in the effects of synthetic phonics instruction depending on the different types of the Phoneme Oddity Task? A total of twelve sessions of synthetic phonics instruction were given to 17 Japanese second-grade elementary school students. The instruction consisted of six activities for English reading and writing. A pretest was administered the day before the first instruction, and a posttest was given three days after the last instruction. For the tests, all participants had a Phoneme Oddity Task. There were two types of tasks in the Phoneme Oddity Task:an Open Oddity task, focusing on the first sound of a word, and an End Oddity task, focusing on the last sound of a word, where the participants tried to identify the odd word out that has different phonetic characteristics than the other three words after listening to four words. The results showed that (1) phonological awareness was improved, and (2) there was no significant difference in the effectiveness of the instruction depending on the type of task.