From a statement issued by the Ministry of Economy in Guatemala:

Guatemala, May 19, 2017. Guatemalan and Honduran technicians decided that during the first phase of implementation, starting next July, the first three border control posts where the Customs Union Model between Guatemala and Honduras will operate, will be El Florido, Agua Caliente-Corinto and Entre Rivers. Other advances reported during the round were that harmonization was achieved of sanitary and phytosanitary requirements, and the pre-check process was defined for cargo transportation drivers.

According to reports, infrastructure designs, signage and traffic flows for the 3 integrated control posts have been done, and they have already started with minor infrastructure works in Corinto, while Entre Ríos will be converted into a Model Border Post.

More on this topic

Honduras - Guatemala Customs Union: How does it work?

June 2017

Which goods can circulate freely and through which border posts, what procedures need to be done and other details about how the customs union functions.

From a report by Agexport:

1.  From now on exports to Honduras will technically be treated as transfers and imports as acquisitions. 

Honduras - Guatemala Customs Union

June 2017

The governments have announced the end of the negotiation process and reconfirmed that operations will start on June 26 at the Corinto border post.

From a statement issued by the Ministry of Economy and Finance of Guatemala:

Guatemala, June 16, 2017. Guatemalan and Honduran officials concluded the negotiation process on Friday of the Customs Union between Guatemala and Honduras, which will officially open on June 26 at the border post in Corinto.

New Border Post between Guatemala and Honduras

August 2016

An announcement has been made of the installation in Corinto, department of Copan, of a third post on the border between the two countries.

The current Free Movement Post in Corinto, located in Honduran territory,
will operate as an Integrated Control Post.

Guatemala - Honduras Border Integration Starts

June 2015

The first stage of the pilot program, which began on June 1, consists of transferring the post of El Florido Guatemala, to Honduran offices in Agua Caliente.

The second phase, scheduled for December, "... involves the installation of "peripheral posts", with which border points will be removed and turned into only crossing and control points, trade will through peripheral positions.