Another massive database where you can search specifically for Golden Time (2013) English subtitles. Quick Tips for a Better Experience
Depending on your region, HIDIVE also hosts the series, often featuring both the subtitled and dubbed versions. Finding External Subtitle Files (.srt/.ass) Golden Time (2013) subtitles
If you already own the media and just need the subtitle files, community-driven databases are your best bet. Look for "fansubs" or official rips on these reputable sites: Another massive database where you can search specifically