The field of Geosciences is very broad and diverse. It has a social science component (the human geography and planning side) as well as a natural science component (the earth sciences side). In addition, Environmental Studies are part of the field; this field of studies itself has a natural sciences side and a policy oriented, social sciences side.
Partly because the University College Utrecht curriculum does not offer many courses in the field of Geosciences itself (you should take as many of these as you can on your side of the ‘divide’), you may have to go ‘shopping’ elsewhere to be optimally prepared. Consider taking an off-campus course in the field; if you go on exchange, select one or more courses in geosciences while you are abroad. Choose an appropriate topic for your 15 ECTS Bachelor thesis which should deal with a topic that is relevant for your choice of Master's specialisation.
Given the limited range of courses at University College Utrecht in the field of Geosciences itself you should take the type of courses in other disciplines that will give you an extra argument in your application. That would apply to courses in the fields that are supplementary in the Bachelor programs. Check these BA and BSc programs to see which ones are required for the particular specialisations. For Human Geography master programs that would apply to research methods and statistical analysis, but a choice of Economics, Sociology or Anthropology would be useful as well, depending on the type of specialisation you aim for. Political Science courses would also be an option since Geosciences often have a strong policy orientation. To prepare yourself, look at the requirements as specified for the different Master's programmes. Several have a pre-Master's programme, often for students with a Bachelor diploma from a University of Applied Sciences (Polytechnic or HBO) and the courses offered in such programmes will show the requirements/expectations of the Master's programmes. These offered courses may be very useful to fill a gap in your preparations.
The Graduate School of Geosciences at Utrecht University offers a large choice of Master's programmes (e.g. Human Geography, International Development Studies, Innovation Sciences, Sustainable Development). These programmes cover the traditional broad field of Geosciences, all taught in English. Many of these programmes require a single year (60 ECTS), often divided between 4 or 5 course modules during one semester and a thesis/internship during the remainder. The Research Master in Urban and Economic Geography and the Sustainable Development programme require both two years of study (120 ECTS). A rather technical programme offered in the Graduate School of Geosciences is the (full-time or part-time) Geographical Information Management and Applications (GIMA), a two-year 120 ECTS programme in various forms of geo information management. This programme is partly distance learning, partly classroom based. Find more details on the Geo master's programs offered at the Utrecht University.
There are some alternatives at other Dutch universities. There are Geosciences faculties – albeit not quite as complete as at the Utrecht University – in Amsterdam (Human Geography and Planning at the University of Amsterdam, including good programs now in Urban Studies; and the Earth and Environmental sciences side at the Free University), in Groningen (also interesting if you want to specialize in the field of Demography) and Nijmegen (Political Geography, specifically Border Studies).
Of course, the number of programmes at universities abroad is limitless, certainly if the wider field of Geosciences is considered. From the perspective of the Geography track at University College Utrecht, the following universities offer interesting programmes and have admitted several of our graduates: the very extensive geography programme at Kings College in London, various Master's programmes at the London School of Economics, and the programme in Development Studies at University College London. Also (Urban) Studies programmes at several other British universities have a good reputation and have accepted University College Utrecht graduates. In Italy some of our alumni have been admitted to the Policy Studies programme of the Johns Hopkins Bologna center – taught in combination with their school in Washington DC. The Polytechnic University of Milan offers an interesting Urban Studies programme that some of our alumni have been enrolled in.