Maria Semyonova (1910-1988) – Docent of the Faculty of Philology of the Latvian State University, Candidate of Philological Sciences. Specialist in the field of dialectology and comparative grammar of the Russian and Latvian languages. >>

Ulyana Semyonova (1952) – as a member of the USSR basketball team twice won the Olympic gold medals (1976, 1980). The best Latvian basketball player of the 20th century. >>

Yakov Serafimov (1884-1949) – a teacher  of Math at the Riga city Russian gymnasium (former Lomonosov). >>

Julia Serafimova (née Baskakova; 1887–?) – a singer and vocal teacher, adocnt of the Latvian Conservatory. >>

Seraphim (secular name Semyon  Protopopov; 1818–1891) –  a bishop of Riga and Jelgava (1874-1877). >>

Lydia Seraya (1936-2020) –  a teacher of Latvian and Russian. >>

Tarasiy Seredinsky (1822–1897) – an archpriest.
 >>

Nikolay Sergeyev (1876–1951) – a choreographer, teacher and ballet dancer, worked at the Latvian National opera as ballet producer in 1922–1925. >>

Oleg Sergeyev (1932-1996) – Candidate of Technical Sciences, Docent of the Riga Polytechnic Institute. >>

Varvara Sergeyeva (1902–1997) – a Full Member of the Latvian SSR Academy of Sciences, prominent expert in the chemistry of wood. >>