The Emerging Sources Citation Index (ESCI) was created recently, in 2015, but few assessments of its journal coverage have been made. The present study tries to fill that gap by comparing its coverage with that of other international abstracting and indexing (A&I) databases. Using this measure, it is feasible to benchmark this index against the other citation indexes for acceptance criteria. We analysed 6,296 ESCI‐indexed journals, 8,889 Science Citation Index Expanded (SCIE), 3,258 Social Science Citation Index (SSCI), 1,784 Arts and Humanities Citation Index (AHCI), and 22,749 Scopus journals as indexed in July 2017 to determine their inclusion in 105 databases. We found that 19.3% of the ESCI journals are not covered by any other A&I databases, a high figure compared with only 0.5% SCIE, 0.3% SSCI, 0.3% AHCI, and 5.5% Scopus journals. This low coverage suggests that the selection criteria for ESCI journals are not consistent with the overall trend in the other classical citation indexes.