“I don’t know you, you don’t know me, but I am from Ethiopia and I am so excited to talk to you.”

That was the message Roman Tafessework Gomeju had for the stranger on the other end of the phone line when she called a hotel in neighboring Eritrea this week from her home in Addis Ababa, the capital of Ethiopia.

For 20 years, this phone call would have been impossible.

Eritrea gained independence from Ethiopia in the early 1990s, but then a border war broke out between them later that decade, locking the two countries in hostilities and leaving tens of thousands dead.

Cross-border travel was banned, the embassies were closed, flights were canceled and phone calls on landlines and cellphone networks were not permitted between the two countries. Then this week, Prime Minister Abiy Ahmed of Ethiopia and President Isaias Afwerki of Eritrea announced a formal declaration of peace between the two nations. Economic, cultural and diplomatic ties can be forged again.

And now with phone services restored, some people have begun calling strangers, just to say hello.

Ms. Gomeju, 32, remembered hearing stories from her father about the beauty of Eritrea. He had lived in Asmara, Eritrea’s capital, for five years and would tell her about the good food, the clean streets and the friendly people.