Previously women could watch matches on television only.
Lamya Khaled Nasser, a 32-year-old from Jeddah, told Agence France-Press she was proud and looking forward to the match.
Reema said the day marked a historic moment for the kingdom.
Saudi private company on Thursday opened the first vehicle showroom for women only just five months before a decision allowing females to drive takes effect.
"I am proud and extremely happy for this development and for the kingdom's moves to catch up with civilised measures adopted by many countries", she said.
Local media said women would also have their own designated smoking areas.
The first stadium to open its doors to women was in the Red Sea city of Jeddah.
"Family sections" are ubiquitous across the kingdom, allowing married couples, direct relatives and sometimes groups of friends to sit together, isolated from male-only tables at restaurants and in waiting areas at banks and hospitals.
Women joined male spectators on Friday at the domestic soccer league match in the western city of Jeddah.
This set-up of the harsh gender isolation was declared in October 2017, as a part of Crown Prince Mohammed bin Salman's pushy reforms to revise Saudi society and make better the economy.
A decades long ban on cinemas was lifted in December as part of the crown prince's vision to boost the country's entertainment industry.
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